贵金属首饰以其主要成分为()饰品、银饰品、铂饰品和()饰品。
参考答案:金;钯
The Japanese have decided to impose incredibly high tariff on agricultural imports from China. What do you think will ______
A.litter
B.splash
C.ensue
D.encounter
在什么条件下才能对运行中的1100A型氧气分析仪进行维护?