He----- (lie)on the bed and begin to think of the past

He----- (lie)on the bed and begin to think of the past
He----- (lie)on the bed and begin to think of the past

He----- (lie)on the bed and begin to think of the past
He lies on the bed and begins to think of the past.一般现在时
He lay on the bed and began to think of the past.一般过去时

He lay on the bed and began to think of the past

。没法做啊，and平行，begin用的是原型，但是主语是He，begin为什么没用三单或过去式。
楼上正解了 ，时态一定要一致，因为是and平行结构
He lies on the bed and begins to think of the past.
或
He lay on the bed and began to think of the past.