题目

对不同品种的水稻进行对比试验，这种试验方法是（） A . 模拟试验法 B . 优选试验法 C . 移植试验法 D . 强化试验法 答案：BI can’t remember ________ made the teacher give Mary the permission to leave the class earlier.A.that it was whatB.what it was thatC.what was it thatD.that was it what