In the US，constitutional amendment can go into effect after it is approved by _______.
A、a two-thirds vote of both Houses
B、three-fourths of the states
C、two-thirds of the states
D、half of the states
【正确答案】：B
【题目解析】：【考点点击】本题主要考查美国宪法修正案。
【要点透析】美国宪法修正案需经美国四分之三的州批准才能生效。P241
