已知：x6=y4=z3（x，y，z均不为零），则x+3y3y-2z=（ ） A．3

老年患者和新生儿患者均应尽量避免应用的是（）

A．青霉素类

B．红霉素

C．氨基糖苷类

D．呋喃类

E．氟喹诺酮类

简述经纬仪的主要轴线及其几何关系。

Now which are the animals really to be pitied in captivity First, those clever beings whose lively urge for activity can find no outlet behind the bars of the cage. This is most conspicuous, even for the uninitiated, in the case of animals which, when living in a free state, are accustomed to roaming about widely. Owing to this frustrated desire, foxes and wolves housed, in many old-fashioned zoos, in cages which are far too small, are among the most pitiable of all caged animals.
Though pinioned swans generally seem happy, under proper care, by hatching and rearing their young without any trouble, at migration time things become different: they repeatedly swim to the lee side of the pond, in order to have the whole extent of its surface at their disposal, trying to take off. Again and again the grand preparations end in a pathetic flutter of their half wings ; a truly sorry picture !
This, however, rarely awakens the pity of the zoo visitor, least of all when such an originally highly intelligent and mentally alert animal has deteriorated, in confinement, into a crazy idiot, a very caricature of its former self. Sentimental old ladies, the fanatical sponsors of the societies for Prevention of Cruelty to Animals, have no compunction in keeping a grey parrot in a relatively small cage or even chained to a perch. Together with the large corvines, the parrots are probably the only birds which suffer from that state of mind, common to prisoners, namely, boredom.

What is an "outlet" in the context of this passage

A．An opportunity for expression.

B．A place to let.

C．A chance of escape into a wood.

D．An exit for a marketer.

机器通常由原动机、（）和工作机三个部分构成。

A.传递系统

B.电力系统

C.水利系统

根据《华润置地商业物业服务标准》要求，依据食品检验协议对食堂的餐具进行检验，原则上每月不少于（）。

A.1次

B.2次

C.3次

D.4次