This is an illness that can result in total blindness if （）．

单项选择题—How are you geeing on with your work —Oh，I’m sorry．Things aren’t going so well as （）．

A．plans
B．planning
C．planned
D．to plan

单项选择题Water, （） enough, can change into vapour quickly.

A. when heated
B. heating
C. though to be heated
D. when is heated