英文代明詞

(1) The man was a very good basketball player when he was young.

Sentence (1) is the main idea that you want to express, telling people what this man was. So, this sentence should become the MAIN clause when combined with other clauses to form a complex sentence.

Next, you want to tell people "which" man you are talking about.
(2) The man comes here every morning.
This sentence should be clear enough to point out (single out) that man to make the qualification unique. (That is, if there are a lot of man coming here every morning, it will not be a perfect condition to describe the man)

To make sentence (2) a relative clause (adjective describing the man), you simply replace "the man" by a pronoun which is called "relative pronoun". As "the man" is a person in the SUBJECT position, you use a personal pronoun "WHO". (note: if "the man" is in OBJECT position, you can use either "THAT" or none at all (ie. omit it).

(2) ===> who comes here every morning (relative clause)

Last but not least, you join the two clauses together by placing the relative clause immediately after the SUBJECT ("the man").

The man ^ (relative clause here) was a very good basketball player when he was young.

The same applies to your second sentence.

Hope you'll understand. The main issue is to find the MAIN IDEA!!!

2015-05-27 00:24:47 補充：
rephrasing:
That is, if there are many men (more than one man) coming here every morning, it will not be a perfect condition to describe the man.

2015-05-27 00:34:26 補充：
More ...
note: if "the man" is in OBJECT position, you can use either "WHOM" or "THAT" or none at all (ie. omit it).

The man you were staring at was a very good basketball player when he was young.

這句(1) "The man who comes here every morning was a very good basketball player when he was young."
能不能改為(2) The man comes here every morning who was a very good basketball player when he was young.
答案是 Who 應該用來代表主詞The man所以應該接近主詞,因此第(1)句子是正確.
這句(3) "The nurse who wears a white jacket always comes to the office very early."
能不能改為(4) The nurse wears a white jacket who always comes to the office very early.
答案是如同對(1)及(2)的回答,即(3)正確,而(4)則否.

"The man who comes here every morning was a very good basketball player when he was young."
The man a very good basketball player when he was young.

這句 "The nurse who wears a white jacket always comes to the office very early."
能改為 The nurse always comes to the office very early.


這句 "The nurse who wears a white jacket always comes to the office very early."
能改為 The nurse wearing a white jacket always comes to the office very early.

All underlined words are telling us more about the subject.- the man & the nurse.

who=pronoun(used as the subject, and only of persons; object form=whom)
eg:-(Who is that man ?Do you know who comes here every morning? Who is that nurse? Who do you think she is ?Do you know who wears the white jacket?)
(1)The man----subj.
who comes here every morning------main cl.,adjective cl.,as a defining clause clear,The use of commas in non-defining clauses marks/makes their difference from defining --as shown here.
was a very good basketball player----sub.cl----manner
when he was young-----sub cl.---reason

(2)The nurse----sub.
who wears a white jacket----main cl., adj.cl. as a defining clause to make the meaning of the sentence clear,The use of commas in non-defining clauses marks their differences from defining---as shown here=defining.
always comes to the office very early-----sub.cl.---manner

The use of the interrogative nominative who for the accusative whom illustrated would be marked. Pl. analysis the sentence concerned,
then decide the correct case to be used in grammar.

he was young 同埋 wear a white jacket 是不必要的，可刪除。

代名詞 pronoun