单项选择题
______ comes back first is supposed to win the prize.A....
单项选择题______ comes back first is supposed to win the prize.
The motive for scientific work is sometimes curiosity, ...
单项选择题The motive for scientific work is sometimes curiosity, sometimes ______, and sometimes the love for money.
I won't pay $20 for the cost; it's not worth ______.A. ...
单项选择题I won't pay $20 for the cost; it's not worth ______.
