— I've got a cough and my chest hurts.

— ________. Let me examine you. [ ]

A. Don't mind

B. You should learn to protect yourself

C. Take it easy

D. Keep calm. You will recover soon

蒸馏水和澄清石灰水分别长期露置在空气中，它们的PH变化是（　　）

A．两者都不变

B．前者变小，后者变大

C．两者都变小

D．前者变大，后者变小