begin的過去式和現在分詞怎么寫

　　例句：

　　He began to perspire heavily.

　　他開始大量出汗。

　　Slowly things began to improve.

　　慢慢地，情況開始好轉了。

　　He began to tie his shoelaces.

　　他開始系鞋帶。

　　It was beginning to snow.

　　開始下雪了。

　　The paintwork is beginning to peel.

　　漆面已經開始剝落了。

　　The economy is beginning to revive.

　　經濟開始復蘇。