习惯上划分东西半球的分界线是( )
A:0°经线和180°经线
B:20°E,160°W
C:0°经线和0°纬线
D:20°W,160°E
⑴Is it hot?____ A. It's on the second floor.
⑵What's the weather like in Beijing?____ B. It's warm and sunny.
⑶Where is the library?____ C. Yes,we do.
⑷What time is it?____ D. No,it isn't.
⑸Do you have a computer room?____ E. It's 6 o'clock.
错——____
快——____
轻——____
人的体细胞中有46条染色体,1个体细胞连续分裂3次,可得到____ 个子细胞,每个子细胞中含有____ 条染色体.