1. A student who has studied English for a few years may have a vocabulary of thousands of words. 

2. Between formal and colloquial English there is unmarked English, which is neither so literary and serious as formal English, not so casual and free as colloquial English. 

3. He bought a jeep although his friend advised him against it.

4. Good writing requires general and abstract words as well as specific and concrete ones though it is the latter that make writing vivid, real and clear. 

5. It was raining so hard that they could not work in the fields. 

6. The politician is concerned with successful elections whereas the statesman is interested in the future of his people.

7. The results of the experiment were successful although the school refused to give any help. 

8. He chose to study computer science because of its good employment prospects

9. If Mary hadn't walked very slowly, she would have caught the train. 

10. The meeting will be put off till next week in the event of his not coming