钛种板现在的包边方法是（）
A、环氧树脂贴白棉布法
B、塑料夹条包边
C、沥青塑料薄膜包边
D、透明胶带包边
参考答案：B
It is the third time I_____this school and I began tolike this place _______I came here. [ ]
A. had come to;the first time
B. have come; first time
C. have come to; the first time
D. had come; for the first time
熔剂中（）的CaO含量最高。
A.石灰石
B.白云石
C.生石
