Past tense

If time or resource constraints do not allow for actual making or testing of certain compounds, use prophetic examples. A prophetic or "paper" example "describes a possible route to making an inventive embodiment that has not actually been carried out [9]." If prophetic examples are employed, it is very important that the verb tense of the prophetic examples always be in the present tense (e.g., acid (1) is reacted with amine (2) forming an amide). In the patent world, the present tense distinguishes prophetic examples from actual examples actual examples are written in the past tense. 

Note the appropriate changes in verb tense. Before you do the work, you might use the present or future tense writing about somethingthat hasn t happened yet. During the lab, since you are supposed to write what you ve actually done just after the time you ve actually done it, a simple past tense is sufficient. 

Unnecessary shifts from one tense to another not only sound unskilled, but may obscure meaning as well. For instance, when describing an event in the past, all verbs should be in the past tense. This seems like an obvious point, but tense shifts account for a large share of grammatical errors, and may be easily remedied. 

Example Whenever President Kennedy summoned [past tense] a Cabinet meeting his advisors were [ to be verb, past tense] quick to respond. 

Writing conventions may seem a bit picky to you at this point however, by adhering to the writing conventions of chemists, you take an important step toward sounding like an expert chemist. If you submit a journal article, for example, with improperly formatted units and figures, incorrect abbreviations, and inappropriate verb tenses (e.g., present tense in sentences that are conventionally written in past tense), readers may judge you as a careless scientist and dismiss your work. 

Two writing conventions apply to the Methods section as a whole the use of tense (past or present) and voice (passive or active). Past tense and passive voice predominate in the Methods section however, in some cases, present tense and/ or active voice are also used. Like other writing conventions, the proper use of tense and voice reveals authors familiarity with the expectations of the held, their objectivity, and more expert-like writing abilities. 

The Methods section is largely written in the past tense. In general, the Methods section describes work that was done in the past, making the past tense the appropriate choice. This is different from a lab manual, which gives a set of instructions in the present tense. 

Although the Methods section is overwhelmingly written in the past tense, there are few correct instances of present tense. The general rule of thumb for deciding when to use past or present tense in the Methods section (and elsewhere in the journal article) is as follows ... 

Work done in the past is described using past-tense verbs (e.g., analyzed, built, heated, investigated, isolated, measured, performed, synthesized, tested). Knowledge that exists in the present (and presumably into the future) is described using present-tense verbs (e.g., contains, defines, describes, explains, implies, is expected to, provides, suggests). Present tense is also used to describe fixed features of a custom-built instrument (e.g., length and width). Consider the following examples. In each case, the past tense describes actions taken by the researchers that led to their results the present tense describes information that is expected to be true over time. 

Past tense Height measurements were taken using a nanoscope. 

Past tense The probe was modeled after work described elsewhere (4). 

Past tense Helium gas was used to purge the chamber. 

Each of the following passages contains a present- and past-tense verb choice. For... 

The Methods section is also written largely in passive voice. Passive voice is most often combined with past tense ... 

Inappropriate We heat the mixture to 80 °C. [present tense, active voice] We heated the mixture to 80 °C. [past tense, active voice]... 

Table 3.4 Passive-voice-past-tense combinations commonly used in Methods sections/... 

When you join two sentences that are in past-tense passive voice, each subject must have a verb that is preceded by "was" or "were."... 

Writing conventions Check to be sure that you have used voice (mostly passive) and tense (mostly past tense) correctly. Check your formatting of units and numbers, use of abbreviations and acronyms, and capitalization of compounds and vendors. 

What rules have you created for yourself to remember when to use the present tense and past tense in a Methods section ... 

Both past tense and present tense are used in passages PI—P4. Find instances of both and explain when each is used. Based on your answer, select the right tense for this sentence The data are/were shown in Table 1. 

Unlike the Methods section, which is written primarily in past tense, both past and present tense are used in the Results section. In general, present tense is used (1) to refer the reader to a hgure or a graph and (2) to make statements of general knowledge expected to be true over time. Consider the following examples ... 

Use the present tense in the Results section to refer to a graphic and to make statements about knowledge expected to be true over time in other cases, use the past tense. 

The 15 most freguent past-tense verbs in Results sections, in order of freguency (based on an analysis of 60 Results sections from ACS journals), areas follows ... 

Uses of the past tense and present tense in a Results section... 

Both past tense and present tense are common in the Discussion section. The same rule of thumb introduced in the Methods section applies to the Discussion section ... 

It would sound funny to say, in the past tense, that the functional group had roles in coordination chemistry, implying that those roles are no longer important. In addition to present tense, another verb construction is commonly used when citing others works. Consider the following sentence ... 

Present perfect is typically used to signal that the knowledge gained from work completed in the past is still believed to be true in the present. Present perfect combines has or have with a past-participle verb form, which is usually (but not always) the same as the past tense form (see table 6.2). Note that the use of the present perfect is not limited to this submove you will see it used in other sections of the journal article, as well. 

Native speakers of English will likely hear the difference between the past tense and past participle forms of the verb and use them appropriately, even if they do not know the terminology used to distinguish one from the other. Hence, "it has been showed" will sound wrong and "it has been shown" will sound right. 

The phrases in table 6.3 are often followed by the personal pronoun we (e.g., In the present study, we...). In such instances, we is used to signal the beginning of the authors presented work in the journal article. (Recall that we is also used in Results sections to signal human choice and in Discussion sections to signal interpretative remarks.) Table 6.4 lists some verbs that typically follow we in the fill-the-gap statement. Note that the verbs are in present tense when they refer to what is presented in the paper (e.g., we present ) they are in past tense when they refer to work done in the past (e.g., we measured ). (See table 6.5 for a summary of common functions of verb tense—voice combinations in Introductions.)... 

In this work, we (present tense verbs) In this work, we (past tense verbs)... 

Verb tenses Verb tenses in the abstract are consistent with conventions used in other sections of the journal article. Past tense is used to refer to work completed in the past and to describe results ... 

Verb tense Verb tenses in conference abstracts are consistent with conventions described elsewhere in the textbook (e.g., see tables 4.1, 5.1, 6.5). For example, past tense is used to describe work done in the past (e.g., The rates were measured ), and present tense is used to make statements of fact or state information that is expected to be true over time (e.g., Furans are found in natural products ). Some authors use future tense (in active or passive voice) in conference abstracts to refer to the work that will be presented (e.g., We will present these Endings and The synthesis will be presented ). Others prefer to state such intentions in present tense—passive voice (e.g., The Endings are presented ). 

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