Modals: must, have to/don't have to/doesn't have to, should

Sea turtles are endangered. We ............. protect them. (There's no other choice))

• must

• have to

• has to

• should

People ................ have picnics on beaches where there are sea turtle eggs. (not a good idea)

• should

• must

• shouldn´t

• don't have to

We ............... use plastic bagswhen we go shopping. (Not necessary)

• must

• should

• doesn't have to

• don't have to

We ............... recycle paper. (Necessary)

• doesn't have to

• don't have to

• have to

• has to

People ................. be very careful around mother cats who defend their kittens. (A good idea)

• should

• shouldn't

• must

• mustn't

You ............. use the car everyday. (Not necessary)

• have to

• has to

• don't have to

• doesn't have to

You ................ interact with injured animals. (Not a good idea)

• mustn't

• must

• should

• shouldn't

Animals and people ................ drink water to survive. (There's no other choice)

• have to

• must

• has to

• mustn't