Your son has kept _________ for two hours. You’d better ask him to have a rest.
#51156
A
study
B
studied
C
to study
D
studying
推荐题目
--- You look ______,Paul. What’s the matter?--- I’m having trouble ______ math.
#51056
A
tired, to learn
B
worried, learning
C
frustrated, to learn
D
angrily, learning
 I study math by ____ lots of exercises.
#49928
A
did
B
doing
C
do
D
does
)Why not consider____________ Kunming for your next vacation ?
#49676
A
visiting
B
to visit
C
visited
D
visitor