题干
–What _________ your teacher _________ now?
-He is cleaning his office.
A：are, doing
B：is; doing
C：are; do
D：is; do
答案(点此获取答案解析）
B
–What _________ your teacher _________ now?
-He is cleaning his office.
A：are, doing
B：is; doing
C：are; do
D：is; do
