He highly appreciated their help.

他非常感谢他们的帮助。

He highly appreciated their assistance.

他非常感谢他们的支援。

Your early reply is highly appreciated.

承蒙早日回复，不胜感激。

You early reply will be highly appreciated.

你方若能尽早答复我方将非常感激。

Your early reply will be highly appreciated.

您的早日答复将高度赞赏。