Bobpromisestojoininthefootballmatch

来源：语文精选馆 2.8W

Bob promises to join in the football match ______ he has to help his parents on the farm.

A. if B. as C. unless D. when

【解析】连词用法。句子前半部分意思是Bob许诺要加入足球队，后面是他必须帮助他父母，因此，需要连词“如果不，除非”。