急性感染性心内膜炎并发心肌脓肿的心电图表现为（） A.心房纤颤 B.房室和室内传导阻

某企业本月主营业务收入为1000000元，其他业务收入为80000元，营业外收入为90000元，主营业务成本为760000元，其他业务成本为50000元，营业税金及附加为30000元，营业外支出为75000元，管理费用为40000元，销售费用为30000元，财务费用为15000元，所得税费用为75000元。则该企业本月营业利润为( )元。

A．170000
B．155000
C．25000
D．80000

直销企业及其分支机构不得招募哪些人员为直销员？（公平交易执法岗位）

It is clear that some chemicals can damage the health of animals and humans. (1) , this is not the only problem that (2) be caused by the careless use of chemicals. Chemicals can also (3) the ecological balance of the environment. If the ecological balance is disturbed, the results can be (4) serious.The (5) of DDT illustrates the problem. DDT, a chemical which kills insects, at first seemed to be a perfect answer (6) many problems. It would control insects that caused dangerous diseases, (7) insects that caused billions of dollars of damage to crops every year. Governments permitted and even (8) the use of DDT. Farmers in many countries (9) to spray it on their crops. The (10) results were good. Damage to crops (11) down, and profits went up. However, the chemical had effects which the scientists didn’t see in (12) . First, it also killed insects which were the (13) enemies of the harmful insects and which were therefore beneficial to farmers. Second, and perhaps worse, DDT did not kill (14) harmful insect. A few insects had natural resistance to the chemical. They (15) and reproduced in large numbers. In a few years there were large numbers of insects which were not (16) by DDT, and there were (17) insects which Could act as natural (18) on these new "super-insects". Finally, it became clear that DDT was not solving the insect problem. In fact, it was making the problem worse. It (19) became necessary to find a second (20) for the effects of the first.

第（3）空应选择（）

A．cause

B．harm

C．break

D．disturb

某同学对下列4个实验都设计了两种方案，其中方案一、方案二都合理的是[ ]

选项　　　　实验目的　　　　　　　　　　方案一 　　　　　方案二　　

A．　除去炭粉中少量的氧化铜　　　　　　加稀硫酸 　　　　高温灼烧

B．　证明长期露置的氢氧化钠溶液已变质　加稀盐酸　　　　加澄清石灰水

C．　鉴别硫酸钾和硝酸铵　　　　　　　　看外观 　　　　加熟石灰研磨闻气味

D．　证明稀醋酸溶液呈酸性　　　　　　加无色酚酞试液　　加氢氧化钠溶液

异构化装置反应系统催化剂再生烧焦前加盲板隔离的目的是（）。

A、防止发生爆炸

B、防止烧坏催化剂

C、防止烧坏反应器中心管

D、防止烧坏反应器扇形管