IgG通过胎盘主要决定于哪一部位

The reason for my delay is _____ I forgot my keys.

A.that

B.why

C.what

D.which

Scarcely ______ asleep when the phone rang.

A．had I fallen

B．I had fallen

C．fell I

D．I fell

Scarcely ______ asleep when a knock at the door awakened me.

A．had I fallen

B．I had fallen

C．fell I

D．I fell

A．trade had fallen off

B．the coinage had been sharply debased

C．spending had outdistanced income

D．profits from mining had declined

A．trade had fallen off

B．the coinage had been sharply debased

C．spending had outdistanced income

D．profits from mining had declined

A．the bridge-tender had fallen from his perch

B．the crash had caused much damage

C．the broken light was irreplaceable

D．the bridge-tender overreacted

Mary: Hello, John. How are you feeling now？ Somebody said you had been sick. John: ______

A．Hello, Mary. They must have had me confused with my brother, George. He has been sick all week. I have never felt better in my life.

B．Hello, Mary. Who's sick？ How can I be sick？ I'm as strong as a horse. They must have gone mad.

C．Hello, Mary. How are you？

D．Hello, Mary. I'm quite happy. My wife has fallen ill. And, how about you？

This is the reason ______I have not done my homework.

A．where

B．when

C．which

D．why