The Qing Emperor knew the secret Ye Qingmei hid at the bottom of the lake.

The Qing Emperor knew the secret that Ye Qingmei hid at the bottom of the lake.

The Qing Emperor knew the secret that Ye Qingmei hid at the bottom of the lake.

According to the documents provided, there was no clear mention of whether the Qing Emperor knew the secret of Ye Qingmei hiding at the bottom of the lake.

The Qing Emperor did not know the secret that Ye Qingmei was hiding at the bottom of the lake.

According to the documents provided, it was impossible to determine if the Qing Emperor knew the secret of Ye Qingmei hiding at the bottom of the lake. The documents did not explicitly mention whether the Qing Emperor knew about the existence of the Forbidden Door or its specific content. Thus, it was impossible to determine if the Qing Emperor knew the secret of Ye Qingmei at the bottom of Taiping Courtyard's lake.

According to the documents provided, there was no clear mention of whether the Qing Emperor knew the secret of Ye Qingmei hiding at the bottom of the lake. Therefore, I don't know if the Qing Emperor knows Ye Qingmei's secret.

According to the documents provided, there was no clear mention of whether the Qing Emperor knew the secret of Ye Qingmei hiding at the bottom of the lake.

According to the documents provided, it was currently impossible to determine if the Qing Emperor knew the secret of Ye Qingmei hiding at the bottom of the lake.

According to the documents provided, there was no clear mention of whether the Qing Emperor knew the secret of Ye Qingmei hiding at the bottom of the lake.

According to the documents provided, it was impossible to determine if the Qing Emperor knew the secret of Ye Qingmei hiding at the bottom of the lake. The documents did not explicitly mention whether the Qing Emperor knew about the existence of the Forbidden Door or its specific content. Thus, it was impossible to determine if the Qing Emperor knew the secret of Ye Qingmei at the bottom of Taiping Courtyard's lake.