Phân biệt 4 mẫu bột trắng đựng riêng biệt sau: NaCl, Na2S, Na2SO3, Na2SO4.

Cho hỗn hợp X gồm Al và Mg tác dụng vừa đủ với dung dịch HCl thu được 13,44 lít khí H2 (đktc) và dung dịch chứa 55,2 gam muối. Viết phương trình hoá học, tính % khối lượng từng kim loại trong X

We receive information from radio through ears. A. Visually B. Hardly C. Orally D. Aurally

7.______you(read)_____that novel yet? 8.Look! Aman (call)_________________you. 9.Keep silent ! I (listen )_______________to radio . 10.________you (play)____________badminton now? 11. He(leave)______ home two weeks ago and we (not hear)______ from him since. 12.How _______your children (go)_____________to school everyday? 13.She _________________ (not / watch) TV yesterday. 14. We _________________ (buy) a new car last weekend. 15. Where _________________ (you / teach) before you came here? 16.Yesterday John (go) to the store before he (go) home. 17.When John and I got to the theater, the movie (start) already. 18.My father (work)_______________ for that company for 2 years. 19.They (play)_____________football since 2 pm. 20.Hoa (study)_____________ in the library at the moment. 21.They (go) ____________home after they (finish) ____________their work. 22.When he came to the stadium, the match (already/ begin) _________________ 23.I thanked her for everything she (do) _____________________ for me.

We(not see)______ your father for ages.