the passage contains sentences that I found --------hard to

the passage contains sentences that I found --------hard to I found it hard to belive that he was working for the enemy He found that the problem was hard to solve. complete the sentences according to the passage above 的意思 It's so hard that I can't understand the passage同义句 it is so hard that i can't understand the sentences I found it was hard to finish the hard work on time改为同意句 i found it important to stard hard I found it hard to living. I found ()too hard to learn English? I found it hard to understood I found ( ) hard to study English.A.that B.it C.it's D.its