playing是非动词吗?playing是作为现在进行时吗?

playing是非动词吗?playing是作为现在进行时吗? 为什么【he likes playing compurter games】里playing要加ing,这是现在进行时吗? the boys are haveing great fun playing in the waves是现在进行时吗? He likes playing the piano."playing”是现在进行时,那么“like”为什么要加s? 现在进行时格式应是Be +动词ing 形式,为什么There are many children playing和I s 为什么swim的现在进行时是swimming.play的现在进行时是playing? playing play plays那个是进行时 she is playing the piano now (is playing 是be动词+实意动词—做谓语）吗? He saw his cat was playing with a dag?是过去进行时吗? 现在完成进行时 having finished homework,he went playing They are playing over there.的谓语部分是助动词+实意动词构成的吗?为什么 playing