禁止青少年吸烟是因为 （ ） A．烟内含激素，吸入后会影响正常发育 B．烟内含有害物质，吸入后对呼吸器官有害 C．烟内含有能让人兴奋的物质 D．
如图所示，斜面倾角为，斜面上AB段光滑，其它部分粗糙，且斜面足够长。一带有速度传感器的小物块（可视为质点），自A点由静止开始沿斜面下滑，
— Do you know if Daniel fishing tomorrow afternoon? — I’m not sure. But if he go, I won’t go, either. A. goes, won’t B. goes, doesn’t C. will
将某一经3H充分标记DNA的雄性动物细胞（染色体数为2N）置于不含3H的培养基中培养，该细胞经过两次连续分裂后形成4个大小相等的子细胞。下列有关的
Dear Annie, I have never written a letter to a newspaper before, I have just never felt the need to do such a thing. I have always felt I was quite able to do everything by myself. But now I know I w
已知一次函数的图象经过点A（-2，-3）及点B（1，6）.【小题1】（1）.求此一次函数的解析式.【小题2】（2）.判断点C(,2)是否在函数的图象上.
下列叙述正确的是 ①用植物纤维制造出的机动车燃料，属清洁的可再生能源 ②用甲醛溶液浸泡海产品，使海产品保鲜 ③变质的油脂有难闻的刺激性气
Switching the lights off or wearing a blindfold(蒙眼布)while eating could be a fast way to lose weight, according to scientists. The simple trick works because it stops diners eating for pleasure
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要耗煤的质量为，
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