C. Circle ‘that’ if it can be left out in the following sentences. Underline the emphasized information in each cleft sentence.

(Khoanh tròn từ 'that' nếu có thể bỏ từ đó trong các câu sau. Gạch chân những thông tin được nhấn mạnh trong mỗi câu trống)

1. The scientist introduced the idea, but it was her assistants that completed the work.

2. Don’t thank me. It was everyone’s efforts that we should be thankful for.

3. It was last weekend that he came to see us for the first time.

4. It is to gain experience that we want to take part in this volunteer work.

5. All of my teammates are excellent students, but it is Mary that I admire the most.