China successfully landed a spacecraft ________ Mars in May, 2021.
in
on
at
for
My favorite is art, I think it's really interesting.( )
season
subject
music
sport
____________________?
I need some music CDs.( )
What's wrong
Can I help you
How much are the CDs
Are you all right
Hi, Alice. I wonder ___________.
I often go swimming in the sports center.( )
where you skate
what you do on the weekend
when you exercise
whether you enjoy your weekend
Intelligent house furnishings(智能家居) are __________ used in people's homes these days.( )
widely
luckily
softly
loudly
She didn't leave the school __________ she worked out this problem.( )
as long as
until
since
while