在一般宴席中，冷菜应占宴席成本的A．10% B．15% C．20% D．25%

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

Have you ever wondered why birds sing?   1  After all, you probably sing or whistle when you are happy.

Some scientists believe that birds do sing some of the time just because they are happy.

  2  Their singing is actually a warning to other birds to stay out of their territory. Do you know what a "territory" is? A territory is an area that an animal, usually the male, claims(声称) as its won. Only he and his family are welcome there. No other families of the same species are welcome. Your yard and house are your territory where only your family and friends are welcome. If a stranger should enter your territory and threaten you, you might shout.  3  If so, you have actually scared the stranger away without having to fight him. 4 But he expects an outsider almost all the time, especially at nesting(筑巢) season. So he is screaming all the time, whether he can see an outsider or not. This screaming is what we call a bird' s song, and it is usually enough to keep an outsider away.

Birds sing loudest in the spring when they are trying to attract a mate and warn others not to enter the territory of theirs.

   5  Most of it has to do with attracting males and setting up territories.

A．A bird does the same thing.

B．Maybe you thought that they were just happy.

C．Shouting loudly is just like a bird's screaming.

D．You can see that birds have a language all their own.E. Probably this would be enough to frighten him away.

F. However they sing most of the time for a very different reason.

G. So, just like human beings, birds sing for almost the same reasons.

某社区有12个居民小组，2000户，6000个居民，其中18周岁以上的居民有4000人，根据《中华人民共和国城市居民委员会组织法》，下列情形中，应该召集居民会议的是（）

A.6000个居民提议

B.500户居民提议

C.5个居民小组提议

D.700个18周岁以上的居民提议

可经过后熟过程达到无害化的病畜肉是（）

A.患水泡病的肉尸

B.体温正常的口蹄疫肉尸

C.有轻微病变的猪丹毒肉尸

D.全身结核但未消瘦的肉尸

E.在规定检验部位和面积上囊尾蚴≤3个的肉尸

肺在维持酸碱平衡中的作用（）。

A．排出CO₂是肺唯一的功能

B．对固定酸也有作用

C．通过调节CO₂排出，肺可提高浓度

D．可直接呼出酮体

E．对挥发酸起调节作用

下列关于E试验结果读取说法正确的是（）

A.药敏试条两侧的抑菌圈与试条相交处位于试条上所示上下刻度之间时，读取较低一侧所示的读数

B.药敏试条两侧的抑菌圈与试条相交处不一致时，读取刻度数值较高的一侧所示的读数

C.沿药敏试条边缘生长的细菌线在阅读结果时不可忽略不计

D.出现双抑菌圈时，应读生长未被完全抑制的部分与药敏试条相交的读数

E.接种量过高时，应读90%抑菌部分与药敏试条相交处的读数