填空

1. My brother used to          ( take) part in the basketball match.

2. Many people arc used                    ( walk) after supper.

3. The teacher made every student        ( answer) the questions to the front.

4. Don't give up _        ( try) . I'm sure you can succeed.

5. Why                    (not invite)  your good friend to go there with you?

可促进内质网释出Ca2+的是

A．cAMP
B．cGMP
C．Ip3
D．DG
E．PIP2