单项选择题

According to the man, what sort of safety feature is used on the filters7

A．They become clogged before losing effectiveness.
B．They’re equipped with built-in measuring devices.
C．Their safety, limits are clearly marked.
D．They change color when no longer effective.
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单项选择题
Mohammed Abu Shamallah was sentenced to life in prison for______.
A．his involvement in the protesting at a death sentence handed down against Attar
B．his slaying a Palestinian policeman and being a double agent
C．his opening fire on rioters protesting at a death sentence handed down against Attar
D．his involvement in the shooting of a Palestinian policeman
单项选择题
The author’s purpose of writing this passage is to______.
A．argue for teaching bright and not-so-bright students in the same class
B．recommend pair work and group work for classroom activities
C．offer advice on the proper use of the library
D．emphasize the importance of formal classroom teaching
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