填空，使用括号中的动词的正确肯定形式。
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任务 1 / 10
The biology teacher (explain) a difficult 概念.
任务 2 / 10
Some students (take) notes during the lecture.
任务 3 / 10
The headmaster (speak) in the assembly hall.
任务 4 / 10
A few classmates (prepare) for the final exam.
任务 5 / 10
The whole class (listen) very carefully.
任务 6 / 10
Two boys (argue) in the corridor.
任务 7 / 10
The librarian (organize) the new books.
任务 8 / 10
The football coach (show) a new technique.
任务 9 / 10
My best friend (write) an essay.
任务 10 / 10
The university professors (grade) the papers.