可用于高剂量甲氨蝶呤静脉滴注时解救甲氨蝶呤毒性的抗癌辅助药为（）
A.四氢叶酸
B.亚叶酸钙
C.香菇多糖
D.门冬酰胺酶
E.戈舍瑞林
参考答案：B
弗拉哈迪的贡献在于，他将摄影机不动声色地静静地拍摄下了男人捕猎海豹的全过程，这就是（）的由来。
. It was great joy ________ he received the news that his lost daughter had been found.
A．because
B．which
C．since
D．that
