You know, Bob is a little slow _____ understanding, so…— So I have to be patient _____ him[ ]

Mr. Black’s memory is getting . As a result, he often leaves his keys at home.

Open the window, please. —Certainly. Which one _______ beside the door

This injury could mean him ______ tomorrow’s 110-meter hurdles.

Make sure that your computer room is 100%________of insects because they can really cause trouble to your machine.