Modal verbs

He .............. to change the light bulb. (It wasn't necessary.)

• mustn't

• didn't need

We .............. make fun of other people's appearance. (It's not a good thing to do.)

• shouldn't

• mustn't

• don't have to

You ............ replace all your ordinary light bulbs with energy-efficient ones. (I advise you to.)

• ought to

• have to

• needn't

Pedro ............... to do an assignment on the problem of deforestation in Spain. (It is necessary.)

• had

• have

• has

You ................. buy products made from endangered species. (It is forbidden.)

• shouldn't

• mustn't

• don't have to

You ..........recycle as much as possible. (It's a good idea.)

• should

• must

• has to

Young people ................ respect the elderly. (It's their duty.)

• needn't

• ought to

• must

People ................ hunt endangered species. (It's against the law.)

• don't have to

• mustn't

• shouldn't

You ................. forget to wear sunscreen. (It's not a good idea.)

• needn't

• mustn't

• shouldn't

Experts say that we all .......... try harder to protect the environment. (It is necessary.)

• have to

• has to

• must