单项选择题
A. Off impulse
B. On guard
C. Off guard
D. On impulse
单项选择题 The manager of the company firmly believed that one of the important () sources of new customers was the children’s market.
单项选择题 Whenever the government increases public services, () because more workers are needed to carry out these services.
单项选择题 The Minister’s () answer led to an outcry from the opposition.