"all of them" vs "all of which"

[Anonymous]

In my TOEFL preparation book I have this example,

There are six types of flamingos all, __________ have long legs, long necks, and beaks that curve sharply downward.

On empty line I should choose one of this answers
1. of them
2. that
3. of which
4. they

Ok, 2 and 4 I scratched right away, and I was thinking a little about whether "of them" or "of which" but "of them" sounded more familiar to me (due to movies I guess) so I choosed that BUT I saw later that its wrong. The right answer is "of which".

Can someone explain me why is this? Would it be acceptable to use "all of them" in this exaple, if not where may I use it? Please dont use much grammer in explanation since I dont understand things that way, all my english is based on listening english/usa radio/movies and reading texts/books.
Thanks

 

[Casiopea]

There are six types of flamingos all, __________ have long legs, long necks, and beaks that curve sharply downward.

1. of them
2. that
3. of which
4. they

There's a comma (,) at the end of "all". That comma separates "all" from the phrase "of which". That is, "of which" is not part of "all". "of which" can be deleted without changing the meaning of the sentence:

...flamingos all have long legs.... OK

But,

...flamingos all, have long legs... Not Ok (The comma separates the subject ('flamingos all' from the verb ('have').


And,

...flamingos all, of them have long legs... Not Ok. (The phrase "all of them" is a set phrase. But the comma separates the head of the phrase "all" from its object "of them". So, let's move the comma:

...flamingos, all of them, have long legs... OK (No comma)

The difference between "of them" and "of which" is this: "of which" functions as a modifier, whereas "of them" functions as an object. Objects are keepers (don't separate them from their heads and don't delete them), whereas modifiers can be separated from the words they modify and they can be deleted, just like "of which" in our example:

"There are six types of flamingos all, of which have long legs, long necks, and beaks that curve sharply downward."

All the best,

Cas

 

[RonBee]

In my TOEFL preparation book I have this example,

There are six types of flamingos all, __________ have long legs, long necks, and beaks that curve sharply downward.

On empty line I should choose one of this answers
1. of them
2. that
3. of which
4. they

Ok, 2 and 4 I scratched right away, and I was thinking a little about whether "of them" or "of which" but "of them" sounded more familiar to me (due to movies I guess) so I choosed that BUT I saw later that its wrong. The right answer is "of which".

Can someone explain me why is this? Would it be acceptable to use "all of them" in this exaple, if not where may I use it? Please dont use much grammer in explanation since I dont understand things that way, all my english is based on listening english/usa radio/movies and reading texts/books.
Thanks

The choice depends on punctuation. Unfortunately, the punctuation in the book is in error. There are two possibilities.

• 1. There are six types of flamingos, all of which have long legs, long necks, and beaks that curve sharply downward.
  2. There are six types of flamingos; all of them have long legs, long necks, and beaks that curve sharply downward.

The difference is that in the first sentence the second clause is a dependent clause modifying flamingos. The second sentence consists of two independent clauses. (You could use a period (full stop) instead of a semicolon.)