单项选择题 Anyone who enters into or exits from China should receive quarantine inspection and fill in the__________ faithfully. A、Health Declaration Form B、Health Form C、Declaration Form D、 Health Declaration

单项选择题 三次多项式曲线预测模型中有三个未知变量。    A、正确 B、错误

不定项选择 硫酸制备的焙烧阶段生成SO3是无害的，不会给后续净化工序产生很多问题。