определите отношения подъемной силы аэростата, заполненного водородом к подъемной силе аэростата, заполненного гелием. массой гондолы и оболочки пренебречь 

I. Insert articles where necessary. 
1) Mother wants her … daughter to learn to play …piano and her … son to play …hockey.
2) … highest peak of …British Isles is …Ben Nevis , situated in …Grampian Montains of …Scotland 
3) …plants can’t grow without… water 
4) …water in …lake is always …clean 
5) … John looked out of … window and exclaimed: ”What …fine day ! What ..wonderful weather!”
6) Will you give me …cup of …tea with …milk and …sugar in it?
7) …longest river of …world is…Nile , and …Amazon is …second largest river.
II. Put the verbs in the correct tenses .
1) I ( not to take) you to the cinema tomorrow if you (not to do) your homework 
2) Who usually (to cook) dinner in your family?
3) –Hello , Jack ! I ( to phone) you two hours ago but there ( to be) no answer . What you ( to do) at that time ?- I(to take)a bath and ( not to hear) the bell .-let’s go for a walk .- I’m sorry , I can’t , I ( to make) a report .
4) Here you are! We (to wait ) for you for an hour . 
5) How much salt you (to put )in the soup? It is so salty.
6) The boy (to fall ) and (to hurt ) himself while he ( to play )football , that’s why he (to take) to hospital 
7) When Nick found the bike at last , he (to understand )at once that it (to break ) by his little brother.
8) * The travellers ( to walk )in the rain for many hours when at last they saw a house.
9) * We can’t watch TV now :our TV set (to repair ) . We’ll have to wait for a while .
10) * It (to announce) on the radio yesterday that the ship already (to leave ) the port and it ( to come) to London in two days.

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