C

On Christmas Eve—the night before Christmas Day—children all over Britain put a stocking at the end of their beds before they go to sleep. Their parents usually tell them that Father Christmas will come during the night.

Father Christmas is very kind-hearted. He gets to the top of each house and climbs down the chimney into the fireplace. He fills each of the stockings with Christmas presents.

Of course, Father Christmas isn’t real. In Jim and Kate’s house, "Father Christmas" is really Mr. Green. Mr. Green doesn’t climb down the chimney. He waits until the children are asleep. Then he quietly goes into their bedrooms and fills their stockings with small presents. When they were very young, Mr. Green sometimes wore a red coat. But he doesn’t do that now. The children are no longer young, and they know who "Father Christmas" really is. But they still put their stockings at the end of their beds.

When the children are older, they （）.

A．know that Father Christmas is real

B．ask their mother to fill their stockings with presents

C．know that Father Christmas is really their father

D．know that Father Christmas is really their friend

如图中，在开关S断开瞬间，

①立即熄灭的是（）；

②逐渐熄灭的是（）；

③突然一亮后逐渐熄灭的是（）。

A.灯a

B.灯b

C.灯c

D.任意灯