接触镜锈斑沉淀物的预防方法为（）。

A、积极治疗眼病

B、改用频繁更换式镜片

C、强护理镜片，防止其扩大

D、不用无防腐剂的生理盐水长期浸泡镜片

It takes a particular talent to be a successful business manager. Business courses can help people to solve management problems, but such courses can do so only for those people with managerial talent. Such people should take business courses to acquire ideas that they can subsequently use to good advantage if management problems happen to arise.
If the statements above are true, which of the following must also be true on the basis of them

A．People who are helped by business courses in solving management problems also have managerial talent.

B．People who are already skilled at solving management problems are unlikely to benefit from business courses.

C．Most ideas that are used successfully in solving management problems are those acquired in business courses.

D．People who lack managerial talent are more likely to take business courses than are people who have managerial talent.

E．(E) Those people who have never taken business courses are unable to solve management problems when such problems arise.