下列词语中，没有错别字的一组是[ ]

A.缄默 　   汲取  　  蓬篙    　截然不同   

B.窥伺   　 污秽   　 慰籍  　  心旷神怡   

C.荒谬   　 踌躇   　 锤炼  　  语无伦次   

D.斫痕   　 琐屑   　 畸形   　 可望不可及

---How long do you think it is ______he took up the job?

--- Half a year at least.

A．when

B．before

C．that

D．since