图为探究酵母菌细胞呼吸的实验装置，锥形瓶装有正常生长的酵母菌及足量培养液，试管装有溴麝香草酚蓝溶液，从阀门通入的空气已去除CO2，实验过
---Is everyone here? ---Not yet．Look，there_______ the rest of our students! A．come B．comes C．is coming D．are coming
在不久前举行的第五届美洲国家首脑会议上，委内瑞拉总统查韦斯送给美国总统奥巴马一本书——《拉丁美洲：被切开的血管》。该书名喻指拉丁美洲
Everyone tries to get to school on time. But when bad weather gives you trouble, can you still make it before the bell rings? In northern China during spring, big sandstorms often make trouble for stu
If you are afraid of the dark，it’s not a big deal．It’s perfectly normal to feel afraid After all，animals do too. “Fear matters，”says Karen Warkentin，an ecologist．“It’s a
地壳中含量最多的元素是（） A．硅B．氧 C．铝D．氢
I won’t call you, ________ something unexpected happens. A. unless B. whether C. because D. while
下列说法不正确的一项是 A.周制：天子地方千里，出兵车万乘；诸侯地方百里，出兵车千乘。 B.后人常用“陶朱”作为富人的代称，陶朱就是范蠡，他
