下列各组物质中：

①CH₃CH₃和CH₄； ②CH₂═CH₂ 和CH₃CH₃；   ③氨气和氨水；④O₂和O₃；

⑤3₂He和4₂He； ⑥CH₃CH₂OH和CH₃OCH₃；⑦氯气和液氯；⑧正丁烷和异丁烷

属于同系物的是____，属于同分异构体的是____，属于同位素的是____，

属于同素异形体的是____，属于同一物质的是____．（填写序号）

在 $\Delta ABC$ 中，AD为BC边上的中线，E为AD的中点，则 $\overrightarrow{EB}=$ (  )

下列各组离子能在指定溶液中共存的是(  )
①无色溶液中：K^＋、Cl^－、Na^＋、H₂PO、PO、SO
②使pH试纸变深蓝的溶液中：CO、NO、Na^＋、S^2－、AlO、SO
③水电离的c(H^＋)＝10^－12mol/L的溶液中：ClO^－、HCO、NO、NH、S₂O
④加入Mg能放出H₂的溶液中：Mg^2＋、NH、Cl^－、Na^＋、SO
⑤使甲基橙变红的溶液中：MnO、NO、SO、Na^＋、Fe^3＋
⑥pH＝0的溶液中：Fe^2＋、Al^3＋、NO、I^－、Cl^－、S^2－

下列化学用语与含义相符的是

用方框中所给的句子填空。请将正确答案的序号填在题后横线上。

Receptionist: ____  Madam?
Alice: I want a single room. I booked（预定）it three days ago.
Receptionist: ____ .
Alice: It’s Alice. Alice White.
Receptionist: Oh, yes. Here it is. You want a single room.
Alice:____  And if it is possible, I’d like a room on the ground floor.
Receptionist: ____  all the rooms on the ground floor have already been taken. But we do have a nice room that overlooks the hotel swimming pool. It is on the second floor.
Alice: Thank you. ____  is the restaurant still open?
Receptionist: I’m afraid not. But you can order room service.
Alice: OK. Thank you