为了安全起见，起动发动机前要检查（）有无行人。---叉车操作和保养手册第2-77.在起动叉车前（）以警告周围的人。
参考答案：周围；鸣响喇叭
It was really noisy in the workshop. Not until ______ at the top of my voice ______ to look at me.
A．did I shout; he turned
B．had I shouted; had he turned
C．did I shout; did he turn
D．had I shouted; he turns
两性生物碱
