单项选择题

在生理学上，两次呼吸的含义是：（） A.
发生在肺部的气体交换以及发生在血液与组织之间的气体交换 B.
指飞行员在紧张时应连续两次深呼吸 C.
指氧气的吸入和二氧化碳呼出两个过程

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单项选择题

In 1856, the first Neanderthal bones were found in Germany’s Neander Valley by workers digging for stones. These thick bones indicated that Neanderthals were shorter than modern humans, but physically stronger. Their tools were rough and simple, and not as refined as those of later Homo sapiens. Additionally, their food was not as varied; the _____________ of their diet was the meat of large and medium-sized animals.
A、trace
B、bulk
C、mainland
D、proof

不定项选择

牛顿切线法的收敛速度：若的单根附近有连续的二阶导数，且初值取在附近，则有．

A．正确
B．错误