I found it hard to fall asleep at night.请问it后为什么不加is.请详细解释

I found it hard to living. i found it important to stard hard I found it hard to understood为什么不是I found it is hard to understood I found it was hard to talk with her=I found () hard () with her I found it hard to answer the question什么意思 i found it hard to learn____（swim）.填空 ,I found it hard to find time to exercise.翻译下特别是 hard to it found it was hard to finish the hard work on time同一句I found 什么 hard 什么什么the hard work on time I found it hard to learn English.对hard 提问,怎么造句? I found it was hard to finish the hard work on time改为同意句I found （ ）hard （ ）（ ）the hard work on time I found （ ）hard to learn to swim.A it B I C he D you 宾语补足语 宾语从句 I found it hard to learn English .I found it is hard to learn English.这2个句子意思都一样吗, 1、I found it very hard to learn English well.(同义句) I found __ __ very hard to learn En1、I found it very hard to learn English well.(同义句)I found __ __ very hard to learn English well,2、It's time foe class now.(同义句)It's time ___ I found ()too hard to learn English?填that 还是it 为什么 Cause it's hard for me to lose In my life I've found i found it hard _____(understand ) him为什么要填to understand I found it was hard to talk with her 同义句 I found it hard ___(understand) him. 填什么?为什么?填to understand 还是 understanding?