1.
1 longest
2 smaller
3 funny
4 nice
5 cleaner
6 largest
7 dirtier
8 worst

2.
Good better the best
Small smaller the smallest
Large larger the largest
Happy happier the happiest
Nice nicer the nicest
Big bigger the biggest
Short shorter the shortest
Bad worse the worst

3.
He must learn new English words.
She can play the guitar.
People should be careful when crossing the street.
Drivers must not drive fast.
May she go to the cinema today?
I can't speak English well.
Children mustn't run here.
You should try again.
I must not come home late.

4.
1 I can't play the guitar.
2 She can't play ping pong.
3 Can you ride a bike?
4 Can your sister drive a car?
5 Can you give the pen to me?
6 It's very hot. Can you open the win downtown?
7 May I go to the cinema?
8 May I use your a calculator?
9 You must learn English words every day long
10 You should read books in English .