当土壤粒径（)mm时，其通气性、透水性则逐渐减弱。A.＞0.1B.＜0.1C.＞0.01D.＜0.01

肺炎链球菌主要的致病物质是

A、荚膜

B、菌毛

C、自溶酶

D、内毒素

E、外毒素

请帮忙给出正确答案和分析，谢谢！

孕妇最常见的营养缺乏病是

A、蛋白质-能量营养不良

B、营养性贫血

C、脚气病

D、干眼病

E、骨质软化病

请帮忙给出正确答案和分析，谢谢！

What is the speaker doing？

A．Explaining the campus architecture to visitors.

B．Providing orientation for new campus employees.

C．Familiarizing new students with the campus.

D．Advising students about which classes to take.

请帮忙给出正确答案和分析，谢谢！

What can we infer from the passage？

A．We are amused by our own acts of absent-mindedness.

B．We are tired of stories about absent-minded professors.

C．Memory "tricks" are nothing dangerous.

D．We can"t hear enough stories about forgetful professors.

请帮忙给出正确答案和分析，谢谢！