企业收到请求后，通过电话、邮件、上门等方式提供服务属于主动服务。()

A. can see distance
B. is able to read eye charts
C. bends the light
D. is working

A. it is interesting but not very useful
B. he says it"s a wonderful invention which could replace eye charts
C. it can be useful but he thinks it"s too early to make a switch
D. too much time and money have been wasted on it

A. Patients have trouble seeing.
B. The ability to focus is gone.
C. No correction is needed.
D. The lens bends the light beams.

A. He doesn"t like the machine.
B. An eye chart is better.
C. It"s what the machine sees in him that is important.
D. The prototype doesn"t work very well.