substitute/replace/exchange 用法辨析

As a substitute teacher, my daily routine involves driving to a new school almost every day so I’m usually unable to anticipate the day’s events, good or bad!
On one particular day, I was teaching in a very difficult classroom. I was managing behavior all morning and by lunch time, I knew I needed coffee to even consider surviving the afternoon. So on my lunch break, I drove to a nearby plaza （购物中心）to get a cup of coffee. Upon returning to the car I realized I had locked my keys and my phone inside! I had about 15 minutes to get back to the school which was a good 4 or 5-minute drive away. I contemplated (思考） sprinting （冲刺）back, but it being winter, I thought a nasty fall on ice would only make the situation much worse.
So I ran into a McDonald’s which was in the same plaza and asked the man at the counter who happened to be the manager to please call me a cab. I briefly explained my situation to him, and I could tell by the look in his eyes, that he empathized. He hurried to the back to use the phone while I paced in the restaurant. I had less than 10 minutes to get back to my school at this point.
The manager returned only to tell me that the cab company had put him on hold and then the line got disconnected, and that he was now on hold again, but had not yet been able to request the cab yet. My expression, I assume, began to resemble some combination of hopelessness and fear.
Without a thought, he grabbed his coat and offered to drive me to the school. Without hesitation, I followed him into his car and made it back into my classroom with 2 minutes to spare before the bell!
Upon arriving at the school, I thanked this man endlessly. His calm demeanor （举止）and kind nature made me think he was probably a wonderful manager to work for, and also a wonderful human being to have on this earth. This experience makes me realize that out of every seemingly hopeless situation, there is the opportunity for acts of kindness to transpire （发生）, which can have an unimaginable impact on those who receive them.
小题1:Why did the author go to get a coffee?

A．Because he needed to eat something as lunch.

B．Because he was very thirsty.

C．Because he had to refresh himself for the classes in the afternoon.

D．Because he wanted something hot to drink.

小题2:What happened to the author after he got a cup of coffee?

A．He fell on the icy road.

B．He realized his keys and phone were locked inside the car.

C．His car was broken.

D．He lost his keys and phone.

小题3:How long probably had the author stayed in the McDonald’s?

A．For about 15 minutes.	B．For about 10 minutes.
C．For about 8 to 9 minutes.	D．For only 2 minutes.

小题4:What kind of person is the manager?

A．Kind-hearted.

B．Active.

C．Good-mannered.

D．Thoughtful.