They have been friends ever since they __________ in grade school. A. are B. have been C. were D. will be
They have been friends ever since they __________ in grade school.
A. are
B. have been
C. were
D. will be
Giải thích:
Although: Mặc dù + mệnh đề
Tạm dịch: Dù mặt trời đang chiếu sáng, trời không ấm lắm.
Choose B.