We must do everything we can _________ our earth clearer and safer.
#49701
A
made
B
to making
C
make
D
to make
推荐题目
The room isn’t big enough for us ________.
#49741
A
to live
B
to live in
C
live in
D
living in
You’d better _______ up late.
#50738
A
not get
B
don’t get
C
get not
D
not to get
This river is too wide for the swimmers _________. 
#48977
A
to swim
B
to swim across
C
to swim in
D
swimming