①O2和O3 ②35Cl和37Cl ③CH3CH3和CH3CH2CH3 ④氯仿和三氯甲烷
⑤CH3CH2CH(CH3)CH2CH3和CH3CH2CH(CH3)CH(CH3)CH3
⑥
⑦CH3(CH2)2CH3和(CH3)2CHCH3 ⑧CH3CH(CH3)CH3和CH(CH3)3
find, eraser, book, some, a, is, my, too, where, under
This is my desk. Two____ are on it. One is my English book, and the other (另一本) is my math book. You can also see (也能看见)____CDs on the desk. The CDs are ____. My pencil box is on the desk,____. A pen,____ eraser and a ruler ____ in it. The pen is black, the____ is yellow, and the ruler is white. ____ is my pencil? Aha, it's under the desk. Is my computer game ____the desk,too? No, it isn't. Where is it? I can't____it in my room.
将17.6克Fe2O3和Cu的混合物溶解于足量的稀盐酸中,再加铁粉9.8克,待铁粉溶解后,溶液中无Fe3+,此过程共产生2.24升H2(标况),则下列判断正确的是( )
“口号”在一定程度上折射和传递这历史信息,下列属于五四运动的口号是( )