已知关于x的方程ax2+2x+1=0至少有一个负实根，则实数a的取值范围（ ）A

月球景观和地球景观相似的是（　　）

A．有风、云、雨等天气现象

B．有碧海蓝天

C．有日光、彩虹和风

D．有平原、高原、山地

We often hear that children wish they were grown-ups, and that old people wish they were young. __小题1:__ The happiest people enjoy what each age gives them without wasting their time in useless regrets.

__小题2:__ A child is fed, looked after and loved by all grown-ups like parents or grandparents. __小题3:__ However, for older people they often lose their interest in those things.

On the other hand, a child may also have some pains with him. __小题4:__ He is often told not to do something. He will certainly be shouted at for doing something wrong.

When a child grows up, he can no longer expect others to pay for his food, clothes and many other things. __小题5:__ If he still spends most of his time playing as he used to in childhood, he will go hungry. If, however, he works hard and has no trouble, he can build up his own position in society with great happiness.

A．What’s more, life is always giving new things to him.

B．He enjoys his life very much.

C．And if he wants to live comfortably, he has to work.

D．He is not so free to do what he wishes to do.E.       Life is always sad for old people.

F.       Each age has its own pleasures and its own pains.

Childhood is a time when there are few duties.

收入、费用和利润三项会计要素表现相对静止状态的资金运动，能够反映企业的财务状况。

患者，女性，32岁。1月前无明显诱因开始发热，体温37．5～38．5℃，持续不退，并盗汗。经抗感染治疗无效，渐出现上腹胀满，腹部隐痛，消瘦、乏力，排黏液便每天2～3次。11年前患肺结核病。月经不调，婚后7年未生育。查体：全腹压痛，腹壁柔韧感，移动性浊音阳性。X线：提示右肺尖结核。

提问：结核性腹膜炎的手术指征是（）。

A.内科抗结核治疗无效

B.并发完全性肠梗阻经内科治疗无效者

C.急性肠穿孔或腹腔脓肿，经抗生素治疗无好转者

D.肠瘘经抗结核化疗与加强营养而未能闭合者

E.诊断困难，与腹腔肿瘤或急腹症不能鉴别时

F.以上都是

全国银行间市场债券回购交易的债券结算通过（）进行。

A.全国银行间同业拆借中心交易系统

B.中央结算公司的中央债券登记簿记系统

C.证券交易所交易结算系统

D.证券公司