We laugh at jokes，but seldom about how they work．

puter ____start, no matter how hard I try.-lt might have crashed.

You had better ________some time every day for sports so that you can keep yourself energetic.

I can ________ the house being untidy, but I hate it if it’s not clean.[ ]

People have planted a great many trees in order to ________ wind and sand in the desert.[ ]