It’s said that an American often starts a speech with a joke, _______ a Japanese seldom does.

It’s said that an American often starts a speech with a joke, _______ a Japanese seldom does.

A．as               B．when             C．while             D．though

It’s said that an American often starts a speech with a joke, _______ a Japanese seldom does.

1. A.
   as
2. B.
   when
3. C.
   while
4. D.
   though