Have you ever heard of Earth Day? When is it? What do you think it is and where is it celebrated? Read the info box and check your answers.
Look at the highlighted sentences in the info box. Complete the rules with the correct tense.
Choose the correct alternative.
Complete the sentences with the correct form of the verbs in brackets.
Write a question using How long? to find out more about each situation.
Complete each pair of sentences with the Present perfect simple and continuous form of one of the verbs below.
Complete the posts with the Present perfect simple or continuous form of the verbs in brackets.