2 Are the underlined words correct? Tick (✔) the correct sentences. Put a cross (X) and correct the word in the incorrect sentences.

Решение:

1. You should buy a ticket before you get on the train! It's essential! [✔]
2. In my opinion, you must always say 'please' and 'thank you'. [✔]
3. You mustn't forget to take the keys! It's very important! [X]
4. In my opinion, you mustn't eat too much sugar. [✔]
5. I don't think we should play football today. The weather's bad. [✔]

Исправление для предложения 3:

You must forget to take the keys! It's very important!