Mark the letter A, B C or D on your answer sheet to indicate the underlined part that needs correction in each of the following questions
When the boulders are made of(A) rock that is different from the bedrock which(B) they(C) or the soil of the field rests, they are called(D) erratics
A. are made of
B. which
C. they
D. are called
Đáp án : B
“which” - > “where” . Ở đây cần một mệnh đề thay để chỉ địa điểm (bedrock)