A、2
B、3
C、4
D、1
答案:B
A. How often
B. How long
C. How many
D. How much
A. Don't
B. Doesn't
C. Aren't
D. Can't
A. π
B. 2π
C. π/2
D. 4π
A. not to watch
B. to not watch
C. not watching
D. doesn't watch
A. symbol;culture
B. symbol;cultures
C. symbols;culture
D. symbols;cultures
A. discussed
B. is discussing
C. was discussing
D. has discussed
A. 0个
B. 1个
C. 2个
D. 3个
A. π
B. 2π
C. π/2
D. π/4
A. Two
B. The second
C. Five
D. The fifth
A. need
B. must
C. may
D. has to