1. Doing outdoor activities is very good ( It ) 

It is very good to do outdoor activities
2. You should wash your hands often ( better )

You had better wash your hands often
3. I prefer drinking fruit juice to soda ( rather )

I would rather drink fruit juice than soda
4. Poor sleep negatively affects our brain ( effect ) 

Poor sleep has a negative effect on our brain
5. Lack of vitamin C in your diet can lead to scurvy including bruising and bleeding easily ( cause ) 

Lack of vitamin C in your diet can cause scurvy including bruising and bleeding easily
6. Men should stop smoking ( give )

Men should give up smoking
7. I'm rather thin. What should I do to gain weght ? ( on )

Can you give me advice on what to do to gain weight?
8. Your sister is active, and your brother is active too ( both )

Both your sister and your brother are active
9. Wash your hands regularly to prevent some diseses ( can ) 

Washing your hands regularly can prevent some diseases