问题
选择题
Although he failed when he tried doing the experiment for the first time, he decided to try it____.
A．once in a while
B．at once
C．once more
D．once
答案
答案：C
本题考查副词短语。句意：虽然他第一次做实验时失败了，可他决定再试一次。once more 再一次, 又一次。