一个句子中出现“be + -ing”时,be的意思应该视具体情况而定。
“be + -ing”构成进行时态的谓语部分时,be是个助动词,没有具体意义,-ing是动词的现在分词。例如:
He is watching TV now. 现在,他在看电视。
My mother was cooking in the kitchen when I got back home yesterday evening.我昨天晚上回到家里的时候,我妈妈在厨房做饭。
be + -ing”构成系表结构时,be是个系动词,意思为“是;存在;成为”等,-ing是动名词或形容词。例如:
Her job is teaching students 2 years ago. (teaching是动名词)
两年前,她的工作是教学生。
It's relaxing to lie on the beach. (relaxing为形容词)
躺在沙滩上令人放松。