[amp_mcq option1=”produced/are becoming” option2=”have been producing/become” option3=”produce/will become” option4=”are producing/became E. were producing/will have become” correct=”option2″]
The correct answer is: B. have been producing/become
The sentence is about the past and the future. The manufacturers have been producing electric cars for a number of years, but they are not yet common. It is likely that they will become common in the future.
Option A is incorrect because the simple past tense “produced” does not express the idea that the manufacturers have been producing electric cars for a number of years.
Option C is incorrect because the simple present tense “produce” does not express the idea that it will be a long time before electric cars become common.
Option D is incorrect because the present progressive tense “are producing” does not express the idea that the manufacturers have been producing electric cars for a number of years.
Option E is incorrect because the past perfect tense “were producing” does not express the idea that it will be a long time before electric cars become common.