. John hadn’t been able to quit smoking at once; he had to control his smoking desire      .

A．more or less

B．by and by

C．little by little

D．now and then

原戴镜者检查视力正确的是（）。

A.先查裸视眼视力，再查戴镜视力

B.先查戴镜视力，再查裸眼视力

C.交替查裸眼与戴镜视力

D.无须查戴镜视力