He took the book out of his bag and began to read.read 在这句里是原型,还是过去式,或过去分词?

begin to do sth 原型呀 固定语法do 就是句中的read ?? sth是??? 这种固定是每个对应还是？？？很多词都有 +to do sth 的结构，是固定的，在多读多看中熟悉，有的是+ do sth 比如had better do sth 有的是+ doing sth 比如insist in doing sthdo 就是 read，后面的sth 就是the book ，只不过他没有写He took the book out of his bag and began to read the book. 加上就重复了，所以不加