Question: Identify the one bold word or phrase that must be changed in order for the sentence to be correct.

1.At 1939, television programs were being broadcast in the United States, and the World's Fair of that year featured demonstrations of this advance in technology.

A) at

B) programs

C) and

D) featured

Its correct answer is (A). Is my reason correct:

My reason: it must be used of the pronoun "in" instead of " at", because sentence tense is past(past continuous)

  1. Scientists usually character the disease leukemia as an overabundance of white blood cells in the bloodstream.

A) character

B) as

C) overabundance

D) in the bloodstream

Its correct answer is (D). why?

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    Welcome to English Language Learners! It is preferred if you can post separate questions instead of combining your questions into one. That way, it helps the people answering your question and also others hunting for at least one of your questions. Thanks! – Catija Aug 18 '15 at 15:08
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    D is not the correct answer on the second question, by the way. – Catija Aug 18 '15 at 15:13

Shin is correct for your first question. "At" refers to a precise time, and "in" is used to refer to a period (a month, a year, a few weeks, and so on). "In 1939" means "at some point during the year 1939", or "Throughout the year 1939".

In regards to your second question, I do not think D) is the correct answer. I believe the correct answer should be A, and the word should be "characterize", a verb meaning to describe the distinctive features or nature of something.


Your answer is correct, but not for the right reason. With years, "at" is simply not used, "in" is used. "At" is used with a particular "moment" in time ("at five o'clock", "at dawn", "at the age of 20").

We can just as well use "in" with years in the future as in the present ("in 2020 the Earth's population will be ...")


Yes and no. Yes, because it should be "in". No, because the correct explanation is:

"at" is used to indicate a PRECISE TIME; and,


Source: https://www.englishclub.com/grammar/prepositions-at-in-on-time.htm

There are tables containing examples in the above source.

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