1 Nick/wash /hands a lot /he / not/ have the flu.

-->Nick washes his hand a lot so he doesn't have the flu.

2 David/ eat/ lots of junk food / he/ not do exercise.

-->David eats lots of junk food but he doesn't do exercise.

3 doctor /told Elena that she/ sleep more/ she/ try to relax more.

-->The doctor told Elena that she must sleep more and she must try to relax more.

4 My sister / play/ computer games / she does exercise too .

-->My sister likes playing computer games,  she also does exercise too. 

5 Eating/ carrot help/ you see objects /more clearly/ at night.

-->Eating carrot help you see objects more clearly at night

6 Going outside / wet hair/ give/ you a cold or flu.

-->Going outside with the wet hair gives you a cold or flu.

7 Eating/fresh fish/make/ you/ smarter.

-->Eating fresh fish makes you smarter.