After playing football for more than half an hour, the students took ______ rest.

A．a ten--- minute

B．a ten minute’s

C．a ten-minutes’

D．a ten-minute’s

关于挖土机械挖土特点说法正确的是( )。

A．正铲挖土机：前进向上，自重切土
B．反铲挖土机：后退向下，自重切土
C．拉铲挖土机：后退向下，强制切土
D．抓铲挖土机；直上直下，自重切土