不能加入S仿真器？

SP无法放置在design上并提示：
an instance of a design cannot be placed within itself,nor within a
design that is part of its hierarchy.
我按照教程做了一个很简单的放大器，不过其中的ＢＪＴ是用的子模块实现的.

大概是ＢＪＴ的子模块没有加进来吧

[m:01]