pick out subjects and predicate
1) a nunber 0f boys were hurt
2)you did youelr duty well.
3)there are eight planets in the solar system
4)excercise makes our muscles strong.
5) close all the doors.

Dear Student,
Remember that subject is the main focus of the sentence and predicate is the remaining part that tells about the subject.
1. A number of boys - subject
    were hurt - predicate
2. You - subject
    did your duty well - predicate
3. Eight planets - subject
    are in the solar system - predicate
4. Exercise - subject
    makes our muscles strong - predicate
5. You - subject (implied you)
    close all the doors - predicate
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