阅读下面短文,从短文后所给的A、B、C、D四个选项中,选出一个可以填入空白处的最佳选项,并用铅笔把答题卡上对应题目的答案标号涂黑。
In Twain, many people know what a “motorpool” means. It is   36  known as a place for the maintenance(维修)of official business and government cars.   37  it is a place for vehicle maintenance.
More than ten years ago I came to America on business and I took advantage of the   38   to visit my friend. My friend drove a car to   39   me at the airport, and took me to his home. Out of the   40 , my friend drove his car into the innermost   41  , which had a sign “carpool only”. I   42   what “carpool” meant. I felt doubted whether he was going to a motorpool.   43   I thought myself clever in asking:
“Is there anything wrong with the car?”
“Nothing.   44  ?” said he.
“Well then, why are you going to carpool?” I   45  .
My friend couldn’t help   46   and told me that“carpool”refers to the lane that only the cars with two or more   47   can drive in. I felt rather embarrassed on   48   that.
After dinner, my friend’s neighbor came over to ask whether he   49   “carpool” the next day.  “ 50  ,” my friend said, “I will accompany my friend to go shopping tomorrow.” I was   51  again, wondering why he could not “carpool” with him since we had “carpooled”   52  . My friend explained to me again that the “carpool” that his neighbor   53   meant they in turn drove the car to work so as to save energy. The first “carpool” is a noun,   54   the second “carpool” is a verb. It is really   55   for newcomers in America to understand it in a short time.

A．commonly B．probably C．partly D．simply

A．In general B．In particular C．First of all D．Above of all

A．break B．time C．chance D．place

A．watch B．help C．meet D．catch

A．house B．airport C．station D．waiting-room

A．road B．lane C．street D．route

A．wondered B．knew C．understood D．learned

A．For B．Thus C．Then D．Though

A．How B．What C．Why D．Where

A．replied B．asked C．explained D．answered

A．saying B．talking C．laughing D．speaking

A．passengers B．drivers C．gentlemen D．ladies

A．noticing B．seeing C．informing D．hearing

A．needed B．could C．should D．would

A．Sure B．Sorry C．Pardon D．Good

A．believed B．doubted C．confused D．worried

A．today B．tomorrow C．yesterday D．tonight

A．used B．insisted C．learned D．provided

A．as B．so C．while D．for

A．interesting B．difficult C．important D．necessary