It (A) is a good idea to be (B) careful in buying or purchasing (C) magazines from salespersons who (D) may come to your?
It (A) is a good idea to be (B) careful in buying or purchasing (C) magazines from salespersons who (D) may come to your door.
A. It
B. to be
C. buying or purchasing
D. who
Đáp án C
Sửa: buying or purchasing => buying hoặc sửa thành purchasingBỏ 1 trong hai đi vì buying = purchasing: mua, tậu, sắm