у лены живут утки и козы. сколько уток и сколько коз живет у лены если считая по головам у нее 25 а если по ногам то 70 ног

запишите уравнения двух реакций (соединения и разложения). при которых образуется алюминий оксид.

Fill in the gaps with must; mustn't; have to, don't have to /
doesn't have to and the verbs visit, touch, go, buy, learn, be polite, walk.
1.    I ... to my guests.
2.    You ... her books. She'll be very angry.
3.    You ... me a new bicycle. My old one is very good.
4.    You ... your granny. She'll be very happy to see you.
5.    I ... to the shop and buy a warm jacket.
6.    Mother ... the dog. We always do it.
7.    You ... this song by heart. Your teacher won't ask you to sing it.