单选题 Who most likely are the listeners?

A、 Safety inspectors
B、 Machine manufacturers
C、 Equipment operators
D、 Medical professionals

【正确答案】 C

【答案解析】解析：题目是询问听者的身份，因此应仔细听与身份和职业相关的内容。通知中提到“…we can get work underway for the day．To avoid any electrical or mechanical accidents while operating our machines，please make sure that you wear protective clothing…”，即在对听者们宣布可以开始进行今天的工作之后，要求大家必须穿好安全服，以防止触电或者机械事故。因此正确答案是(C)Equipment operators。

单选题 What are employees asked to do to avoid accidents?

A、 Wear protective clothing
B、 Report equipment damage
C、 Read a safety manual
D、 Double-check their work

【正确答案】 A

【答案解析】解析：题目是询问为了避免事故，职员被要求做什么，因此应仔细听与题目的中心语avoid accidents相关的内容。通知中提到“To avoid any…accidents…，please make sure that you wearprotective clothing…”，即为了避免事故，请一定穿安全服。因此正确答案是(A)Wearprotective clothing。

单选题 What does the speaker say about the labels?

A、 They are available at the security office.
B、 They cannot be removed until tasks are finished.
C、 They must indicate container's contents.
D、 They are attached to bottles of chemicals.

【正确答案】 B

【答案解析】解析：题目是询问说话者提到的有关标识的内容，因此应仔细听与题目的中心语labels有关的内容。通知中提到“Please do not remove these labels until the experiments are completed．”，即在实验结束前，请不要移走这些标志。因此正确答案是(B)They cannot be removed untiltasks are finished．。