You really need to go out and get some fresh air and sunshine. You _____ overworked during the

last two weeks . [ ]

A. have been

B. were

C. had been

D. would be

楼层地面面层应不易磨损或不易破坏，且表面平整、不起尘，国际通用标准的耐久性一般为( )年。

A．5

B．10

C．15

D．20