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.
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)
- Scientists usually character the disease leukemia as an overabundance of white blood cells in the bloodstream.
D) in the bloodstream
Its correct answer is (D). why?