We can see __sun in the day, and we can see ___many stars at night.

A．the, the

B．a, a

C．the, /

D．/, the

烧结料水分偏低或燃料偏大时，应适当（）点火温度，烧结料水分偏高或燃料偏低时，应适当（）点火温度。