21.(单选题, 2分)Mary found it useful to () a deep breath when she feels nervous.

5.(单选题,2分)The manager put forward a suggestion ()we should have an assistant.There is too much work to do.

4.(单选题,2分)Mary had an () ;she's been knocked down by a taxi.

3.(单选题,2分)Jane had promised to give me a timetable for tomorrow. She failed, ().

2.(单选题,2分)They were angry because you () your promise.

1.(单选题,2分)He had so little education()he was unfit for this job.