написать письмо A visiting speaker recently came to your school to give a talk on peer pressure. Your teacher has asked you to write a letter on behalf of your class to thank her (120-150 words). Include:
• why your class appreciated the talk
•) ) if she can come again and speak to another class

In 1869 the great Russian scientist Dmitri Mendeleyev announced the discovery of the Periodic Law of elements. So science received the key to the secrets of matter.
All the greatest discoveries which have been made since then in the fields of chemistry and physics have been based on this law.
The elements in Mendeleyevs Periodic Table follow one another in the order of their atomic weights. They are arranged in periods and groups.
Mendeleyev s discovery made it possible for the scientists to find 38 new chemical elements to fill the empty spaces left in the Periodic Table.
At the same time they tried to find elements heavier than the last element in the Periodic Table.
In 1955 the American scientist Dr. Glenn Seabord obtained element No 101 and named it Mendelevium in honour of the creator of the Periodic Law.

1 I (switched off ) the computer because it (was making) a strange noise.

2 My dad (was listening) to classical music when I (arrived) home from school.

3 We (were playing) video games when my mum ,(said) ‘Turn the volume down!’

4 My cousin (met) his wife, Bianca, while he (lived) in Italy.

5 My little sister (was drawing) a picture while I (was studying) for my French exam.

6 While they (were trying) to fix the computer, all the lights (wentout).

7 When we (left) school yesterday, it (was pouring) with rain.

8 When you (saw) Paul, he (was wearing) a black jacket?

9 I (was trying) to log on when the WiFi (stopped) working.

10 While Dad (was printing) an article, the printer (ran out) of paper