减压炉进行烧焦时炉管颜色以（）为宜，发现炉管过红应立即关小通风量。
A.暗红
B.桃红
C.深红
D.粉红
参考答案：A
现定义两种运算“ⓧ”“*”，对于任意两个整数，aⓧb=a+b-1，a*b=a×b-1，则8*（3ⓧ5）的结果是______．
Scientists say it may be five years _____ it is possible to test this medicine on human patients.[ ]
A. since
B. until
C. before
D. when
