Now that I having grow old , I often spend a lot of time thinking about my childhood.

Options

A. had grown older
B. has grown older
C. No improvement.
D. am growing older

Answer

D

Explanation

having grow old should be replaced with an growing older . Present Continuous is used to express the idea that something is happening now, at this very moment.
However, the given sentence is in the simple present tense, so the former part which is in . continuous tense should also be in the simple present form.