对圆筒形工件纵向焊缝探伤时，跨距将（）
A.增大
B.减小
C.不变
D.以上A和B
参考答案：D
The supermarket offers __________ goods to choose from, so more and more people prefer to shop
there. [ ]
A. particular
B. various
C. general
D. common
青皮升高血压的主要成分是
A．去甲乌药碱B．对羟福林C．黄酮苷D．氢氰酸E．氯化甲基多巴胺
