耐药机制主要是产生超广谱β-内酰胺酶的细菌是（） A.军团菌 B.耐甲氧西林的金黄色

Students under 16 years old shouldn't _____ to go to the Internet bar (网吧). [ ]

A. allow

B. allowed

C. be allowing

D. be allowed

软体动物约有10万种，指出下面贝壳已退化的软体动物是

A．乌贼

B．田螺

C．扇贝

D．河蚌

Mr. Brown is warm-hearted and often does everything that he can to       to those in trouble.

A．break out

B．set out

C．reach out

D．pick out

下肢骨包括哪些？各有何主要结构？

枝红色的树木有（）

A、红瑞木

B、榆叶梅

C、李

D、野蔷薇