and和that在定语从句里可以连用吗

可以 当后面的定语从句有多个时，后面的必须and +that 

and that 表示一种“承前启后的”作用，意思“而且，并且”

如：

It seems to me now that he sighed and that I tittered to hide my embarrassment.在我现在看来，他那时似乎在叹气，而我吃吃地笑是在隐藏我的尴尬。

The computer can even type letters you dictate to it， and that， in any language you choose.计算机甚至能把你口授给它的信件打出来，而且能用你所选择

that 在这里的用法是“用于强调先前表达过的词或短语的意思”，其前的 and 用于承前启后。and that 在此可翻译成“而且”。

如：

He was fed up， and that to a great degree.  他已吃饱，而且相当撑。

and that 的习惯用法：

She came at midnight， and that alone. (and that＝and she came at midnight)

He studied music for many years， and that under a well-known musician. (and that＝and he studied music for many years)

The boy has lost a book， and that the one he bought only the other day. (and that＝and he has lost)