Bears ______ fat stores throughout the summer and fall to have energy enough to last them through winter sleep.

A．build up

B．pack up

C．bring up

D．take up

盖堵法抢护漏洞进水口时，须防止从覆盖物周边进水，覆盖后应立即（）。

A.铺盖沙石滤料

B.封严周边并迅速盖压闭气

C.铺设梢料

D.盖压沙土