The water in the river nearby will be dirtier than before if nothing __________.

Tim, where is the other sock? You should learn to _______ your things.

I met a friend of mine_________ in the street yesterday.We didn’t meet on purpose. [ ]

Excuse me, I want to buy some food. Where can I find a supermarket？ —I know _____ not far from here. You can easily find ________.

We missed our train, and ___ the next train was delayed, ____ we had to wait for two hours.