—Life is full of opportunities for you.

—That’s right. _____ .

A．It’s my cup of tea.

B．I have butterflies in my stomach.

C．It will cost an arm and a leg.

D．The world is my oyster.

下列变化中，属于化学变化的是

A．海水淡化

B．氢气吹肥皂泡

C．煤燃烧

D．干冰升华