Read these sentences and choose 'must' or 'mustn’t'. 1.We (must/mustn’t) send SMS during the lesson. 2.You (must/mustn’t) work hard. It is important. 3.You (must/mustn’t) turn the music too loud.

1. We mustn’t send SMS during the lesson.

Explanation: During the lesson, it is important to pay attention and focus on the teacher and the material being taught. Texting or using a phone can be distracting to both the student and the teacher, and it can disrupt the learning environment. Therefore, it is necessary to refrain from sending SMS or using a phone during the lesson.

2. You must work hard. It is important.

Explanation: Working hard is crucial for success in any endeavor, including school. By putting in effort and dedicating oneself to the tasks at hand, one can achieve better results and improve their understanding of the subject matter. Therefore, it is advised and necessary to work hard in order to achieve academic success.

3. You mustn’t turn the music too loud.

Explanation: When studying or doing homework, it is important to have a quiet and focused environment. Loud music can be distracting and make it difficult to concentrate on the work at hand. Therefore, it is necessary to avoid turning the music too loud while studying or doing homework, as it can hinder productivity and comprehension.