在油松的发育过程中，下列哪些细胞染色体数为单倍（） ["珠被细胞","珠心细胞","胚乳细胞","胚细胞"]
工资支付的原则包括（） ["协商同意","平等付酬","紧急支付","依法支付"]
The amount of fluid delivered by a helical pump can be regulated by （）. ["throttling the pressure line","changing the speed of the rotor","either A or B","None of the above is tree"]
Which of the following pumps are self-priming, and can deal with liquid from a level below the pump? （） (1) reciprocating (2) rotary (3) centrifugal ["(1)only","(1)and (2)","(1),(2)and(3)","(2)and(3)"]
在PowerPoint 2003中，在一张幻灯片中可插入另一个演示文稿。
什么是碘泡虫病？
