我国第二阶梯和第三阶梯的分界线是( )
A:大兴安岭﹣长白山﹣太行山﹣武夷山
B:大兴安岭﹣太行山﹣巫山﹣武夷山
C:昆仑山﹣祁连山﹣横断山脉东缘
D:大兴安岭﹣太行山﹣巫山﹣雪峰山
⑴____ what when
⑵____ who where
⑶____ whose here
⑷____ white well
⑸____ walk why
⑹____ weather which
(Ⅰ)求角B;
(Ⅱ)若sinA= 33 ,求△ABC的面积.