读一读,找出下面句子的回答,把相对应的英文字母填在横线上。。
①Give me a ruler, please.____ A. Hi! Danny.
②Good afternoon, Kitty.____ B. Good morning.
③Here you are.____ C. Here you are.
④Hi. I'm Danny.____ D. Good afternoon, Alice.
⑤Good morning.____ E. Thank you!
如图所示,挂在弹簧测力计下的铁块置于一个匝数可变的电磁铁的上方。当开关S与1接通稳定后测力计的示数为F1,使滑动变阻器的滑片P向左移动到某一位置,弹簧测力计的示数为F2,则F1____ F2;然后滑片P的位置保持不变,开关由1接到2,稳定后弹簧测力计的示数为F3,则F3____ F2。(选填“=”、“>”或“<”)
南北回归线是( )
①热带和温带的分界线
②温带和寒带的分界线
③有无阳光直射的分界线
④回归线上一年仅有一次阳光直射.
体液
血液
唾液
胃液
pH
7.35~7.45
6.6~7.2
0.9~1.5
⑴What did you do yesterday?____ A. I am going to play basketball.
⑵What are you going to do?____ B. I am playing football.
⑶What are you doing now? ____ C. I played pingpong.
①干冰 ②氢氧化钙 ③甲烷 ④硝酸铵固体