thereof thereafter thereto thereon......等等这一系列词是什么意思？怎么用呢？什么词性？

thereof adv. 关于...; 由此, 因此

eg. Take therefore no thought for the morrow. Sufficient unto the day is the evil thereof.

所以，不要为明天忧虑; 因为明天自有明天的忧虑; 一天的难处一天当就够了。

thereafter adv. 其后, 从那时以后

eg.You'll be accompanied as far as the border, thereafter you must find your own way.

有人送你到边境，然后你必须自己走了。

thereto adv. 另外, 到那, 往那里

eg.They signed the agreement and the documents appended thereto.

他们签署了协议与附件。

thereon adv. 在那上面, ...之后立即

Draw a view of this element with the stress placed thereon.

画出此单元体,将应力标在其上。