题目

下列化肥分别与熟石灰混合研磨后，能闻到刺激性气味的是( ) A. NH4Cl                         B. KNO3 C. NaNO3                         D. Ca3(PO4)2 答案：A ________ the house Mr Smith has been broken into? [　　] A．When was it that B．When has C．Has D．Had