Решение:
- Jack spoke so quietly that c. the teacher didn't hear him.
- The party was so noisy that a. Leo's neighbour complained.
- Mike drove so fast that b. he was last in the race.
- Tom's results were so good that f. his parents gave him a present.
- Dave ran so slowly that e. he arrived very early.
- My dad got up so early that d. he was tired by lunchtime.
Ответ: 1-c, 2-a, 3-b, 4-f, 5-e, 6-d.