【题目】—How are you getting along with your German, Kate？
—Oh, Mr．Black, I’m so tired of it．Maybe I should drop out _____ it kills me．
A．when B．after C．while D．before
在线课程【答案】D
【解析】Drop out,退学，退出。根据句意，从句它烦死我（“it kills me”），与主句我可能该退学（“Maybe I should drop out”）构成“在……之前”的时间关系，选从属连词before。