As作连词引导时间状语从句时,着重强调主句和从句中的动作同时发生,并且从句通常放在主句之前.归纳起来有下列两种情况:
1)状语从句的谓语动词是持续性动词,从句时态常用进行时态.
如:①AsheWaswaiting,hesuddenlyheardavoicefromabove……
②AsBethuneandtheotherdoctorswereclimbingthehills,theycouldseetheenemyenteringthevillageinthevalleybelow.
2)状语从句的谓语动词是终止性动词,从句时态常用一般时态.
如:①Asshestoodthere,sheheardthefirstbell.
②Astheylookedup,theysawanothercloudcomingtowardsthem.
③Astheywatched.itcamenearerandnearer.