那有多种情况：

　　如果后面是宾语从句,则通常是与过去有关的时态

　　Hesaidthathewasathomeyesterday.(was一般过去时)

　　HesaidthathehadbeentoBeijingtwice.(hadbeen过去完成时)

　　Hesaidthathewouldgohometomorrow.(wouldgo过去将来时)

　　HesaidthathewaswatchingTVateightyesterdayevening.(waswatching过去进行时)

　　Hesaidthattheearthgoesaroundthesun.(goes一般现在时)

　　只有在所说的话是真理的情况下用一般现在时.

　　如果后面不是从句,那就通常用动词不定式、动名词、分词等形式.也就是非谓语形式.（较复杂,最好看语法书）

　　如

　　Hewenttobuyapen.(tobuy)

　　Heenjoyedplayingcomputergamesyesterdayafternoon.(playing)

　　Hesawtheboycomeoutfromtheroom.(come)

　　太多了,打起来麻烦,这要上语法课都要上很多节的,一下二下难说清楚的.