80％的传染性单核细胞增多症的患者有______、______及______三联症。

在一个淡水生态系统中，其中一条食物链是：微小的水生植物→剑水藻→蜻蜓幼虫→小鱼→大鱼，当这个淡水生态系统被排放的难以分解的有毒物质污染后，体内有毒物质的富集量[ ]

A．微小的水生植物最高          

B．大鱼最高

C．各种生物一样高            

D．活的时间长的作物最高

下列插管长度不妥的是（）

A.大量不保留灌肠：7～10cm

B.小量不保留灌肠：7～10cm

C.保留灌肠：10～15cm

D.肛管排气：7～10cm

E.男患者导尿：22～24cm

如图所示，一均匀的长方体橡皮，重为0.3N，侧放于水平桌面上时，与桌面的接触面积是10^－3m²，此时它对桌面的压强是________Pa；若沿ab方向竖直向下切去一块，则剩余部分对桌面的压强________ （变大/变小/不变）；若沿如图所示的对角切去上方一半，则剩余部分对桌面的压强_________ （变大/变小/不变）。切削前后橡皮的密度_______ （变大/变小/不变）.

桥梁构件选用（）

A.40

B.Q345

C.2Crl3

D.65Mn

What does the speaker mean a. He cooperated with his friends and set up a business together. b. He was given a lot of advice by his friends in setting up his own business. e. His friends gave him much financial support in setting up his own business. d. His friends encouraged him to set up his own business.