主语+Be动词和主语+动词的区别
主语+Be动词和主语+动词这两种用法怎么区分呢?比如说He was thinking about a maths problem.和 He thought about a maths problem.
是这样啊 那比如现在时（同样时态的）主语+Be动词和主语+动词这两种的句型的话怎么区分用呢？我每次都分不清楚。