▲回答如下：

(1) 以上不是同位语从句，而是由it充当形式宾语，that从句充当真正宾语的句子结构

(2) 句子结构为 see to it (形式宾语) + that 真正宾语从句

(3) see to 意思"照料;处理;照看；注意"

特别备注：see to 后面不能直接接宾语从句，需要在宾语从句前加上一个“形式主语it"其结构为see to it +that 从句。

▲关于动词后面需要接it形式宾语在接真正宾语动词归纳如下：

动词 hate, like, take , owe, have, take ...for granted, love, dislike,depend on, rely on, appreciate, enjoy ,answer for, feel like, be fond of, count on 等表示“喜欢”“痛恨”“认为”等的动词或短语和 see to 后面不能直接跟宾语从句，必须先加 it 形式宾语，然后再接宾语从句：

结构(1) 主语+hate+it+宾语从句

I hate it when they talk with their mouth full of food. 我讨厌他们满嘴食物讲话.

When you start the engine, you must see to it that the car is neutral. 启动发动机的时候，一定要使汽车的离合器处于空档位置.

结构(2) 主语+like +it+宾语从句

结构(3) 主语+take+it+宾语从句

I take it that you don’t agree with me.

结构(4) 主语+owe+it+宾语从句

结构(5) 主语+have+it+宾语从句

结构(6) 主语+take +it for granted +宾语从句

Some students just take it for granted that they will pass the exam. 有些学生想当然地他们能通过考试.

结构(7) 主语+appreciate+it+宾语从句

I will appreciate it if you can help me.

结构(8) 主语+depend on +it+宾语从句

You may depend on it that they will support you.