1. This is a group of about 10,000 volunteer doctors who help sick people everywhere.

(What is the antecedent of the relative clause, "who-"? 1) a group of about 10,000 volunteer doctors
2) about 10,000 volunteer doctors )

2. This is a group of Korean and foreign middle school students who help small children in poor parts of the city.

(What is the antecedent of he relative pronoun clause, who -? 1) a group of Korean and foreign middle school students 2) Korean and foreign middle school students)

1. This is a group of about 10,000 volunteer doctors who help sick people everywhere. OK

(What is the antecedent of the relative clause, "who-"? 1) a group of about 10,000 volunteer doctors
2) about 10,000 volunteer doctors )<~~The antecedent for "who" is "doctors." The other words are not relevant in determining the antecedent.

2. This is a group of Korean and foreign middle school students who help small children in poor parts of the city. OK

(What is the antecedent of he relative pronoun clause, who -? 1) a group of Korean and foreign middle school students 2) Korean and foreign middle school students) The antecedent of "who" is "students."

1. The antecedent of the relative clause "who-" is "a group of about 10,000 volunteer doctors." To determine the antecedent, you can ask yourself: "Who are the volunteer doctors that the relative clause is referring to?" In this case, it is the group of about 10,000 volunteer doctors that the clause is describing.

2. Similarly, in this sentence, the antecedent of the relative pronoun clause "who-" is "a group of Korean and foreign middle school students." To find the antecedent, ask yourself: "Who are the middle school students that the relative clause is talking about?" The answer again is the group of Korean and foreign middle school students that the clause is referring to.