单项选择题
In vain ______ to get in touch with the Embassy.
单项选择题 He operates the new machine as if he ______ special training in it.
单项选择题 The new secretary has written a remarkably ______ report only in a few pages but with all the details.
单项选择题 I hope that the little ______ I've been able to do has been of some use.