兩題英文句型文法結構問題~

With a built-in handle and weighing only 20 pounds, Buoy is designed to go wherever you go.
因為一個句子只能有一個動詞，所以原本的weigh (V) 重......，要變成動名詞，所以要加ing。

你可以看成 Buoy weighs 20 pounds and is designed to go wherever you go.
前面主詞刪掉，動詞變動名詞，Weighing 20 pounds, Buoy is designed to go wherever you go.

2.After all, people are not supposed to stay planted in one spot all day.
這裡的planted 是PP (過去分詞) 當形容詞用。

又如：You just stay put.

希望對你有所幫助嚕

2014-01-15 09:05:28 補充：
是耶! 是分詞構句
現在已經沒有辦法修改了，怎麼辦，囧!

題1.：

With a built-in handle and weighing only 20 pounds, Buoy is designed to go wherever you go.

請問動詞"weigh"後接"ing"是根據何種原因而成?

weighing only 20 pounds是一個分詞片語
與介系詞片語with a built-in handle
都是述部的修飾語（屬副詞性質），修飾is designed to go wherever you go表示是以這種方式來設計的。
因為修飾語越位到主詞之前，所以用逗號與主句隔開。


題2.：

After all, people are not supposed to stay planted in one spot all day.

請問"plant"後接"ed"是根據何種原因而成?

planted是過去分詞（表示被動），放在屬於不及物動詞的不定詞stay後面當作［補語］。
本句的主句是用被動結構，邏輯上的受詞people成了形式上的主詞，而原來當［受詞補語］的不定詞片語to stay planted ...留在原地。

2014-01-15 08:57:02 補充：
Weighing 20 pounds, Buoy is designed to go wherever you go.
這句前面的weighing ...不是動名詞，而是分詞，用來當述部的修飾語，屬於副詞性質。
在句中當主詞，受詞等屬於名詞性質的Ving才是動名詞。

原句也可寫成：Buoy, which weighs 20 pounds, is designed to go wherever you go.

(1)The chair=Buoy
With a built-in handle and weighing only 20 lbs., Buoy is designed to go wherever you go.
In the sentence; is designed=verb
weigh (verb)--->weighing=gerund used as a noun;
Hence:-Weighing (gerund) 20 lbs. , Buoy is designed (verb) to go....
Hence=Buoy weighs, designs......are two verbs.
designs=one verb;
"weighing" referring to gerund used as a noun.
(2)Participial---consisting of a participle and other words used only adjectivally;
Hence participial adj.
After all, people are not supposed to stay planted in one spot all day.
participial=adj
present participial=planting
past participial=planted
Hence:-People stay planted(=referring to participial past:-planting ; planted ; planted .)
Thanks for the time consumed away in answering.