Tỉ khối hơi của 1 khí so với khí khác( mà trong khí đó có nhiều chất) thì tính như nào nhỉ??

giải hai đề này dùm mình với ..

Giúp e câu này với E cảm ơn trước ạ

một người bán rau được 120000 đồng biết người đó dã lãi 20% so với số tiền mua tính số tiền vốn ban đầu

1: Mary has answered the teacher’s question...? A: has he B: Didn’t she C: Hasn’t she 2: Your coat got we yesterday.....? A: Didn’t you B: Didn’t it C: Doesn’t it 3: I’m early....? A: am I B: are not I C: aren’t I 4: Those plates are very dirty....? A: are they B: aren’t they C: weren’t they 5: Mrs.Lan was sick....? A: was he B: wasn’t she C: isn’t she 6: The costumes look gorgeous....? A: don’t they B: can’t they C: can you 7: My pen is blue . His pen is red...? A: isn’t he B: aren’t I C: isn’t it 8: We designed our own house....? A: Didn’t they B: did we C: didn’t we 9: It’s getting colder ....? A: is it B: isn’t it C: isn’t he 10: Everyone has left the dangerous area...? A: haven’t they B: isn’t it C: are they 11: Everything happens for a reason....? A: is it B: doesn’t it C: aren’t they 12: Everyone must observe traffic regulations...? A: must they B: mustn’t they C: mustn’t we 13: Hardly a day goes by without thinking of her..? A: is it B: does it C: doesn’t it 14: She has never been to Ha Long Bay....? A: has she B: hasn’t she C: is she 15: Someone has told him about her death....? A: have they B: haven’t they C: hasn’t he

1- That woman be Spanish but I am not sure. She sounds Spanish though. 2-What I do? Do you think I should go to the party with Michael? 3 - You park here. You will get a parking fine if you do. 4-You. have called Sally. I have already called her. 5-I speak English when I was young but now I 6-You wear a helmet if you ride a motorbike. 7-Mandy - go to Rome next year but she is not sure. 8- Take an umbrella. It _snow if the temperature goes down. 9-You walk. I can give you a lift if you want. seen that film. It's one of the best films I've ever seen. 11-I hope I - pass all my exams and go to university next year. 12- They be out. All lights are off. We __come back tomorrow. 13-You - use your mobile phone at the cinema. Turn it off! - told me Peter has already got a girlfriend. 15-She heard the phone ringing. She had her headphones on. 16-Tom told me he swim when he was four. His parents taught him. 17-You shout at me. I am not deaf! 18-He go to the military service last year. 19-My car is filthy. I_ wash it before the wedding. 20- Charles, do you think you - pass your driving test soon? 21- The meeting has finished. You leave now if you are not feeling well. 22-Your eyes look red. You _ been crying. What's wrong? 23-In my opinion you visit your aunt. You haven't seen her for a long time. 24-Serena, I use your mobile, please? I left mine in the office. 25-1 come with you if I had known George was there. 00000D 26-1 wear a uniform when I was a flight attendant. Q T 27-Shelley come for the weekend if she can book a flight. 28-Sorry Amanda. You _ - use my computer. You broke it last time you did. 29-You - speak Spanish here but English, otherwise you'll never learn. 30-Pat be so stubborn and go to the doctor's when she's not well. 31-You _seen that film. They are still shooting it. have a lot of money. 32-She's wearing a fur coat. It looks expensive. She 33-You step on the grass. You are not allowed to. - have seen that play. It was grec 34-We went to the theatre last night. You _ 35-We hurry to catch the train. We've got plenty of time. 36-You be exhausted. You have been working all day non-stop.​

By the time (return) home from England next month, they (already / build) a new house for him.

nam nặng 34kg.trọng lượng của nam là

Giải phương trình sau x(x+1)-(x+2)(x-3)=7

Đốt cháy hoàn toàn 8,96 lít khí CH4 (đktc), toàn bộ sản phẩm cháy dẫn vào dd chứa 22,2 gam Ca(OH)2 thì khối lượng của dung dịch tăng hay giảm bao nhiêu gam?