1
2
3
4
100

3.20 1

I had to walk.... 

100

3.20 5

don't enjoy having to....

100

3.20 6

we had to pick up....

100

3.20 8

they needn't worry...

200

3.20 2

You'll need to wear.....

200

3.20 3

you mustn't drink....

200

3.20 4

we didn't have to pay  OR

we didn't need to pay

200

3.20 10

we needn't have brought OR

we didn't need to bring

300

3.21 1

Contradiction....can't

300

3.19 2

optional....don't need to do

300

3.21 4

Disbelief...can't

300

3.19 4

recommended...don't need to

400

3.19 1

prohibited....must not do

400

3.21 2

Inference...must

400

3.19 3

mandatory....must be done

400

3.21 3

Conjecture...must

500

3.16 A

(1) can't

(2) may

(3) couldn't

500

3.16 B

(4) may not

(5) could

(6) may

500

3.16 C

(7) might

(8) may

(9) Could

500

3.19 5

expedient...need to do