It's important for us to do A and do B还是It's important for us to do A and to do B.

It's important for us to do A and do B
不定式符号to这里不再重复
如：
It's important for us to do our part and not abuse the planet。
native speaker写的文章中出现的句子。

第二个吧，and并列各种一致是需要的

1 IT'S IMPORTANT FOR US TO GO AND TELL HIM ABOUIT OUR TRAVEL PLAN.
2 IT'S IMPORTANT FOR US TO REMEMBER HIS KINDNESS TO US AND AT THE SAME TIME NOT (TO) FORGET TO THANK HIM FOR THAT.本回答被提问者采纳

Yes

第一种吧