人类的遗传物质主要存在于（ ） A．细胞质中 B．细胞膜中 C．细胞核中 D．细胞的各个部分
下列叙述正确的是 A．同主族元素从上到下，元素原子得电子能力逐渐减弱，表现在氢化物的稳定性逐渐减弱，熔沸点逐渐升高 B．除稀有
某2 .0 L硫酸溶液中含有1.0 mol H2SO4。试计算： （1）溶液中H2SO4的物质的量浓度； （2）向上述溶液中加入足量的铁粉，产生气体的体积（标准状况）； （
下列反应中硫酸既表现氧化性，又表现酸性的是 A．氧化铝和硫酸B．氧化铜和硫酸C．硫化氢和硫酸D．铜和浓硫酸
Self-confidence, motivation, support and knowledge are the main factors determining if one succeeds or fails. Each of these factors influences our chances of success in a different way. 16 .
Is this the reason he explained at the meeting for his carelessness in his work? A. what B. how C. that D. why
--- I found your foreign friends didn’t laugh a lot over my jokes. ---Don’t be silly. You know culture differences? Being a foreigner, he didn’t ____these jokes. A. catch on
You’d better come back earlier _______ it is getting colder. A. as B. and C. but D. or
在下列哪个区间上为增函数 
B．
C．
D．
