Туристы прошли 56 км. 15% пути они прошли по горам, 55% пути - по равнине, а остальной путь шли по лесу. Сколько километров прошли туристы по лесу?​

в каком случае существительные пишутся с предлогом об и в каком случае с о

Помогите:

1)Here are some facts about the life of a British astronaut,Helen Sharman.Use the cues to write sentences about her in the Present Perfect. 

Example:

1.She hasn't been to the Moon.

1.not be to the Moon

2.write a book about space exploration

3.not see a UFO

4.give a lot of interviews

5.not meet any aliens

6.not star in a film

2)Complete the sentences with ever, never or just.

1.Have you ____ seen a UFO?

2.Scientist have ____ discovered another planet in our solar system.

3.I've  ____ read a book about aliens - it was fascinating.

4.People have ____ got any signals from space.

5.I've ____ seen a science fiction film - I'm not interested in them.

антоніми до слів:чудово,радісно,довго,ясно,уміло,швидко і ніжно.