体弱便溏者忌服的是（） A.天仙子 B.生千金子 C.巴豆 D.生半夏

阅读综合填空。

     Every morning, Jim (1)g______ to work by bus. As (因为) he has a long way to go, he always

(2)b______ a newspaper.It helps him to make the time pass (过) more (3)q______. He reads the

sports page. There is a report on an important football (4)m______. He is so interested in it that he

forgets to get (5)o______. He knows this when he looks (6)o______ of the window and sees the

sea. He gets off at another station and (7)h______ to wait a long time for a bus back. Certainly, he

is very (8)l______. His boss (老板) is very angry. He shouts at (9)h______. "Don't (10)b______

late next time."

某气体单质和氧气的相对分子质量比为7：8，则该气体可能是（　　）

A．CO

B．CO₂

C．N₂

D．Cl₂

小明在实验室里测量一块形状不规则、体积较大的矿石的密度．

（1）他把托盘天平放在水平桌面上，将游码移到标尺左端零刻度线处，发现指针偏向分度盘的左侧，此时应该把平衡螺母向       （选填“左”或“右”）调节，才能使天平平衡；

（2）天平平衡后，把小石块放在左盘，用镊子向右盘加减砝码，当把砝码盒中最小的砝码放入右盘后，发现指针偏向分度盘的右侧，接下来正确的操作步骤是              ，直到天平再次平衡，此时右盘中砝码和游码的位置如图所示，矿石的质量是     g．

（3）因矿石体积较大，放不进量筒，因此他利用一只烧杯，按图所示方法进行测量，矿石的体积是       cm³,

（4）矿石的密度是           kg/m³，从图A到图B的操作引起的密度测量值比真实值           （选填“偏大”、“偏小”、“不变”）．

活化热钾碱法主要用于合成气脱碳。

活动弯头可旋转（）度。

A.45

B.90

C.120

D.360