---Have you heard of Earth Day? --- Yes, We have only one Earth. We have no choice but ________ it.
#49067
A
protect
B
protected
C
protecting
D
to protect
推荐题目
I often see my mother __________ chess with my father after supper.
#48889
A
to play
B
played
C
play
D
playing
－Have you seen Mr. Black these days, Jack?－Yes, I met him when I ________ in the street yesterday.
#49575
A
walked
B
was walking
C
have walked
D
is walking
---I often chat with my friends on the Internet.---You are so smart! Will you please tell me ________?
#49449
A
how to do
B
how to do it
C
how to use
D
when can I use it
My family consider a computer, which is considered a great help in our work and study.
#50363
A
to buy, to be
B
buying, being
C
to buy, being
D
buying, to be