Sure! Here are the rewritten sentences:

1. Although I had imagined my parachute jump would terrify me, it was actually quite exciting. **BEING**
**Being a far more exciting experience**, my parachute jump was quite thrilling.

2. They’ve made a decision about the new site for the supermarket. **REGARD**
**They regard it as** the new site for the supermarket.

3. The medicine may not be pleasant tasting, but you must take it anyway. **HOW**
**You must take the medicine,** however unpleasant it tastes.

4. I can’t believe how quickly you have reached the top position in the company. **RANKS**
**You rank at the top position** of the company.

5. Did anything about his behaviour seem unusual to you? **STRIKE**
**Did anything strike you as** unusual about his behaviour?