Fill in the gap with a suitable phrasal verb in the box. [ look for ; turn off ; look after ; go on ]. He will ... his mother

V. Fill in the gap with a suitable phrasal verb in the box.
[ look for ; turn off ; look after ; go on ]
1. He will ____________his mother.
2. If we ______________ wasting water, there will be a shortage of fresh water in a few decades.
3. I think we should _____________ the faucets when we don’t use.
4. I’ve lost my keys. Can you help me to______________ them?