The fact has worried many scientists the earth is becoming warmer and warmer these years.
A. what B. which C. that D. though
If one succeed， one must put his heart into his career.
A. will B. is going to C. is to D. is about to
The book was written in 1946， the education system has witnessed great changes.
A. when B. during which C. since then D. since when
My wallet isn’t in my bag. Where I have put it？
A. can B. must C. should D. shall
Many children may be fond of animals， but ever think of making the study of animals their career.
A. a few B. few C. some D. any
The country has already sent up three unmanned spacecrafts， the most recent at the end of last March.
A. has been launched B. having been launched
C .being launched D. to be launched
