122. And scores of online discussion boards have popped up on which people discuss negative experiences tied to too much time on the Web.
譯文
網上突然出現(xiàn)了很多討論區(qū)，專門討論花太多時間上網的負面體驗。
點睛
本句的主干是boards have popped up。on which引導的是以online discussion boards為先行詞的定語從句，起補充說明作用，其中過去分詞短語tied to too much time on the Web作negative experiences的后置定語，tied與negative experiences為被動關系。
pop up的意思是“突然出現(xiàn)，冒出來”。如：
After the rain, mushrooms seem to pop up overnight. 下過雨后，蘑菇似乎一夜之間就冒了出來。
tie...to...的意思是“使緊密結合”。如：
Our success is tied to you. 我們是否成功和你緊密相關。
考點歸納
過去分詞短語作定語時，通常放在所修飾的詞之后，實際上相當于一個定語從句。如：
These are problems left over by history.＝These are problems that/which are left over by history. 這些是歷史遺留下來的問題。
I like the idea presented by my dad.＝I like the idea that/which is presented by my dad. 我喜歡爸爸提出的主意。
She is the first nurse trained by their country.＝She is the first nurse that/who is trained by their country. 她是她們國家自己培養(yǎng)的首位護士。
