***** NOT A TEACHER *****
IF (if!) I understand my books correctly, you are absolutely correct.
1. "It is easy to think of a plan."
a. "Obviously," the word "easy" is an adjective. (Compare: "To think of a plan is easy.")
b. The comparative makes no difference:
i. "It is easier ("more easy") to think of a plan than to carry it out."
2. "I was ten minutes late." (Forget "for the train" when analyzing the status of "late.")
a. My books tell me the grammatical meaning of this sentence is: "I was late to the extent of ten minutes."
I = subject.
was = linking verb.
late = adjective.
ten minutes = noun phrase being used as an adverb to modify the verb. [Important edit: Please see MikeNewYork's post.]
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