these sentences and choose 'mustn’t' or 'needn’t'. 1. You smoke in here. It's forbidden. Look at that sign.

2. They do the washing up, they have a dishwasher.

3. You buy these clothes. You have enough at home.

1. You mustn't smoke in here. It's forbidden. Look at that sign.

Explanation: The phrase "It's forbidden" suggests that smoking is prohibited in the given location. In this case, the correct choice is "mustn't" because it expresses a strong prohibition or obligation not to do something.

2. They needn't do the washing up, they have a dishwasher.

Explanation: The presence of a dishwasher indicates that there is no necessity or obligation for them to do the washing up manually. Therefore, the correct choice is "needn't" which implies that they are not required to perform the task.

3. You needn't buy these clothes. You have enough at home.

Explanation: The statement suggests that there is no need or requirement for the person to purchase these clothes because they already have enough clothing at home. Hence, the appropriate choice here is "needn't" which indicates that there is no obligation or necessity to buy the mentioned clothes.

In summary, "mustn't" reflects a strong prohibition or obligation not to do something, while "needn't" indicates that there is no necessity or obligation to perform a certain action. It is essential to carefully analyze the context of each sentence to determine the appropriate choice.