—Why did you plant so many trees? — ______ the environment.
#49943
A
Improve
B
To Improve
C
Improved
D
Improving
推荐题目
— I tried       it out in this way, but I failed.— Why not       it in some other ways?
#50281
A
to work; try doing
B
to work; try to do
C
working; try to do
D
to work; to try doing
When I returned .I saw him ____ on the bed.
#50772
A
laying
B
lying
C
lay
D
lie
Would you please   me how to do it ? 
#50447
A
tell
B
telling
C
to tell
D
not to tell