(本小题满分12分) 在△ABC中,a, b, c分别为内角A, B, C的对边,且 (Ⅰ)求A的大小; (Ⅱ)求的最大值. 答案:解: (Ⅰ)由已知,根据正弦定理得 即 由余弦定理得 故 ,A=120° ……6分 (Ⅱ)由(Ⅰ)得: 故当B=30°时,sinB+sinC取得最大值1。 ……12分I ___________ to phone her all day, but whenver I phone her, the line is engaged.A.triedB.had been tryingC.have triedD.have been trying