SAT试题类型 Writing > Identifying Sentence Errors

The following sentence contains either a single error or no error at all. If the sentence contains an error, select the one underlined part that must be changed to make the sentence correct. If the sentence contains no error, select choice E.

Farmers a who grow major crops such as corn, rice and wheat, b aware that new developments in agricultural production can result in millions of dollars in additional revenue, c switching to newer, d more efficient technologies.  e No error

(A) 
(B) 
(C) 
(D) 
(E) 

答案:C

Explanation

The error in this sentence occurs at C.  The participle “switching” cannot function as the main verb of the sentence and should be replaced by the present tense verb phrase “are switching.”