Max often knocks our books __________ the floor when he walks ________our desks.

A qualified doctor has to constantly update hisknowledge in order to maintain his professional _____.

After P.E., I often feel very thirsty. —Why not buy some ________ to drink

The book is here somewhere, but I couldn’t it just now.[ ]

(2013·贵州模拟)Tom, clean up the broken glass　　　someone walks on it