帮我解决英语难题(汉译英12）

1.He doesn't regret for saying that,but he thought he could have done it in another way.
2.We'd better wait David untill Dec.14th.At that time,he will have finished his exam,and we can go for a vacation.
3.He is nowing working on a new project,and he must accomplish it before the end of the year.
4.They allow us to use their laboratory,and in return,we allow them to share the result.
5.It took me up a whole day to type this paper.