Если M, N, K, P - середины сторон четырехугольника ABCD.
Проведи диагонали четырехугольника ABCD, тогда MN = PK и MN||PK (как средние линии треугольников ABC и ADC с одним основанием AC), MN=PK = AC/2, и MN||AC||PK.
Аналогично для NK и MP - это средние линии треугольников BCD и BAD с одним основанием BD, тогда NK=MP= BD/2, NK||BD||MP.
По определению параллелограмма: MNKP - параллелограмм.
My Favourite Season - AutumnI like autumn very much. The autumn months are: September, October, November.<span>In September summer yields to autumn. The days become shorter and the nights become longer. The sun rays are not so bright and warm. The fruit trees that not long ago bloomed with flowers are heavy with juicy apples and pears. Harvest time is a rush season for farmers. They gather sunflowers and maize, potatoes and cabbage, turnip and cucumbers, carrots and tomatoes. Early autumn is the period of flaming colours, when the landscape is gold and brown. In the daytime the silver gossamer is flying in the air. It’s a sign of the beautiful “Indian Summer”. But unfortunately this period of fine weather is very short and deep autumn follows it.</span>
1) september
2) july
3) march
4) may
5) november
6) february
7) april
8) june
9) august
10) october
11) january
Summer and Winter
1. Sent to the doctor immediately
2. At this picture often look.
3. His report always listen with interest.
4. These letters will be reviewed tomorrow.
1.came
2 .finished
3.have never been
4.did you see
5.cooked
6.have already studyed
7.spent
8.learnt.go
9.is washing
10 i hane not resived..........yet
11was training