Verb-Tense Consistency Across Clauses
Question
When she arrived at the lab, she realizes that the experiment had already been concluded.
Answer choices
- NO CHANGE
- realized
- has realized
- was realizing
B Correct answer: B) realized
The clause "When she arrived" is in simple past. The action of realizing happened at that same past moment, so the main verb must also be in simple past: "realized." The pluperfect "had already been concluded" is fine in the second clause because it indicates an even earlier completed action.
The other options either introduce a grammatical error or change the intended meaning. The ACT consistently rewards the most concise, grammatically correct option.
Read the sentence with each option substituted in. The version that preserves meaning while obeying the underlying rule is the correct answer; on the ACT, that is almost always the shortest option that still works.
The underlying rule
A subordinate clause introduced by "when" plus a past-tense verb ("arrived") establishes the tense of the entire sentence as past. The main-clause verb must be in simple past unless there is a clear reason to shift.
Why each wrong answer is wrong
- A) NO CHANGE: This is a verb tense that is inconsistent with the past-tense framing established by "When she arrived."
- C) has realized: This is a verb tense that is inconsistent with the past-tense framing established by "When she arrived."
- D) was realizing: This is a verb tense that is inconsistent with the past-tense framing established by "When she arrived."
Study tip
If a sentence opens with a "when," "after," or "before" clause in past tense, the main verb is almost always going to be past tense too. Tense shifts within a single sentence are rare on the ACT and almost always wrong.
More Hard Grammar & Usage
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