句子是否通顺？

1. 这个句子不对，这是一个it is+adj.+不定式的句型，其中，it是形式主语，不定式充当真正的主语，所以不能用no difficulty，而要用not difficult，变成：
It's not difficult for us to come up with some possible factors to account for this trend.
或者用名词no difficulty，可以改成there be句型：
There is no difficulty for us to come up with some possible factors to account for this trend.
2. 这个句子也不对，主要是后面那个are found cars，我们把它还原成主动句：
We find approximately 55% of families in Chinese big cities cars made in China.
明显这个句子是有问题的，因为find 这个词不能跟双宾语，不像give..
正确的应该是：It’s reported that, approximately 55% of families in Chinese big cities are found （to have) cars made in China.

有点啰嗦。。。
格式： it's +形容词+for sb. +to do

it is not difficult for us to come up with some possible factors that can account for this trend