判断，正确的画“√”，错误的画“×”。

( ) 1. The flag of the U. S. is red, white and yellow.

( ) 2. The president of the U. S. lives in the White House.

( ) 3. Statue of Liberty isn't in New York.

( ) 4. Canada is north of the U. S.

( ) 5. China is west of the U. S.

( ) 6. The capital city of the U. S. is Washington, D. C.

对于抑制性突触后电位的产生，正确的叙述是（）

A.突触前轴突末梢超极化

B.对Ca²⁺、K⁺通透性增大

C.突触后膜出现超极化

D.突触后膜去极化

E.突触前膜去极化