It is necessary _____ something to protect our environment.
#50188
A
do
B
to do
C
does
D
doing
推荐题目
Don’t forget ________ the lights before you go to bed.
#49236
A
turn off
B
turning off
C
to turn off
D
turns off
--- It’s too hot. Would you mind _____ the door? --- ______. Please do it now.
#50610
A
to open ; OK
B
to open ; Good idea
C
opening ; Of course
D
opening ; Certainly not
