第33题: [单项选择]______ luck would have it, we arrived in time to catch the 8:00 o'clock flight to Madrid. A. Which B. As C. Before D. Because 参考答案:B 答案解析:本句为一个非限定性定语从句,从句引导词代替整个主句的内容,而C和D均与题意不符。非限定性定语从句中能用关系代词代替整个主句的只有which和as两个,其中,which通常只能居于主句之后,而as则既能