He is a thoughtful and qualified father; He ____some time every day to read to his children.

A．sets down

B．sets off

C．set out

D．set aside

套铣筒是解除管柱被砂卡、水泥卡及落物卡等事故的（）工具。

A.管形

B.筒状

C.杆型

D.环型