耙吸挖泥船所用的IHC耙头属于（）耙头。 A.冲刷型 B.挖掘型 C.吸入型 D.混

书面表达。

     下面四幅图画描述了你某天放学后发生的一件事。请你根据这些图画的内容用英语写一篇80词左右

的日记，时间是2007年6月8日，星期五，天气有雨。日记开头已给出。

     June 8, 2007                                                      Friday                            rainy

     This afternoon, when I walked out of school, the weather changed. _______________________________

_________________________________________________________________________________________

_________________________________________________________________________________________

下列各项中，哪项是有机磷农药中毒的发病机制（）

A.乙酰胆碱活性降低，胆碱酯酶积聚

B.胆碱酯酶活性降低，乙酰胆碱积聚

C.胆碱酯酶活性增高，乙酰胆碱减少

D.乙酰胆碱被水解为胆碱及乙酸

E.胆碱酯酶不被磷酰化

（多选）某物体的位移—时间图象如图所示，则下列叙述正确的是(      )

A．物体运动的轨迹是抛物线

B．0—4s物体运动得越来越慢

C．4s—8s物体向正方向做加速运动

D．8s内物体运动的路程是160m

国家层面限制开发的重点生态功能区的开发管制原则不包括( )。

A．严格控制开发强度，逐步增加农村居民点占用的空间
B．重点规划和建设资源环境承栽能力相对较强的县城和中心镇
C．加强县城和中心镇基础设施建设
D．开发矿产资源、发展适宜产业和建设基础设施，要做到绿色生态空间面积不减少

Here is a new idea in agricultural weed control. Rather than trying to formulate herbicides that kill specific weeds but are harmless to grain crops, use a broad-spectrum herbicide effective against all kinds of plants and use genetic engineering specifically to make the crops impervious to the herbicide.
Which of the following, if true, is the most serious obstacle to an implementation of the new idea outlined above

A．Certain herbicides that are effective against specific weeds can inhibit the growth of certain crops as much as two years after application.

B．Research to date suggests that the nutritional properties of crop plants would not improve as a result of the genetic alterations being contemplated.

C．Most herbicides that kill only a narrow range of targets contain active ingredients that are harmful to domestic animals and wildlife.

D．Effective broad-spectrum herbicides are on the market, but their very effectiveness has so far rendered them unsuitable for agricultural weed control.

E．(E) Although genetic modification has made individual plants of grain species resistant to broad-spectrum herbicides, the seeds that such plants produce will not sprout.