Word Forms:

1. Skateboarding is a challenging, sometimes dangerous sport. (skateboarding)
2. His speech impediment is affecting his keenness in the soldiers. (keen)
3. John is good at French but weak at history. (history)
4. Some of his conclusions are mathematically impossible. (mathematical)
5. She has given the police a very detailed description of the robber. (descriptive)
6. We watched scenes of the dramatic rescue on the news. (dramatic)

Rewrite the Sentences:

1. I have not tried to learn a foreign language before.
   I have never tried to learn a foreign language before.

2. First, I went to the supermarket, then I prepared the meal for my girlfriend.
   Before I prepared the meal for my girlfriend, I went to the supermarket.

3. Tom started learning the guitar a month ago.
   Tom has been learning the guitar for a month.

4. When Mary heard the results, she began to feel more self-confident.
   Since hearing the results, Mary has felt more self-confident.

5. How long have Helen and Robert been married?
   When did Helen and Robert get married?

6. I haven't gone to the cinema for two weeks.
   I last went to the cinema two weeks ago.

7. I have not smoked cigarettes in years.
   I stopped smoking cigarettes years ago.

8. I met my best friend when we were 11.
   I have known my best friend since we were 11.