焊工必需持有（）才能上岗作业。
参考答案：焊工证
His company _____ into a big one. [ ]
A. expanded
B. stretched
C. extended
D. reached
（）用于含多量矿物质药物制备大蜜丸。
A.嫩蜜
B.中蜜
C.老蜜
D.蜜水
E.生蜜
