I saw a man entering the house secretly.完全不懂时态,请指教,

I saw a man entering the house secretly.完全不懂时态,请指教,
I saw a man entering the house secretly.
完全不懂时态,请指教,

I saw a man entering the house secretly.完全不懂时态,请指教,
这是过去进行时,你不懂时态是因为这是一个从句.I saw a man (that he is) entering the house secretly.你可以理解为是两句用从句的形式合并成了这一句,这样就好理解了.