Basic grammar questions of subject and predicate

[李育睿]

Hi everyone:
I'm a junior English learner. And I just start reading some online English grammar tutorial. The following are practice questions in the tutorial.

Question 1 : What is underlined words?
All roads Leads to Rome.
A. Subject
B. Predicate
Answer : A. Subject


Question 2 : What is underlined words?
A sick Room should be well aired.
A. Subject
B. Predicate
Answer : B. Predicate

I don't understand why Question 1's answer is "Subject" and Question 2's answer is "Predicate". Could someone help me?

[Dunchee MA]

The answers are wrong.