— Are you willing to live on Mars one day?— It sounds exciting,but it still worries me.
We all know that learning a foreign language ______ time and effort.
I find ____ useful _____ English well.
----Do you like chatting with your friends on the telephone or mobile phone? ----_________. I would rather __________ QQ.
We may meet all kinds of difficulties in the future, but we should be confident enough to _______any challenges.
______ your parents strict_____ you _____ your study?