在电气设备上工作，保证安全的组织措施（）.
A、工作票制度
B、工作许可制度
C、工作监护制度
D、监护人制度
参考答案：A, B, C
_______over everything whenever we want to make a decision, many people believe, and we will have less chance of making mistakes.
A．Think
B．Thinking
C．To think
D．Thought
—Why, my new computer is rubbish! Five hours has passed and it still hasn’t finished the downloading.
—Don’t worry. You know, sometimes the Internet ________ be very slow.
A．can
B．may
C．should
D．must
