I don’t want to eat, _______ I am very thirsty. ( )

A．so

B．and

C．or

D．but

This knife is old ______ sharp. (    )

A．and

B．or

C．but

It is beautiful now, ________ it wasn’t beautiful then. (　　)

A．and

B．but

C．so

用所给词的适当形式填空。
ring    cry    but   come   watch
1. My father is working on the computer, but my brother starts to ________.
2. My mother is cooking dinner, but the bell ________.
3. “Come in，please!” I say. My friend Lucy ________ in.
4. Mr Smart is reading a book and Mrs Smart ________ TV.
5. Lin Tao is doing his homework, ________ the phone rings.

Spring is good _______ winter is my favorite season.（  ）

A．and

B．because

C．but