Have you ever heard of Cao Wenxuan，a writer from Jiangsu？
Of course．______，he is a good friend of my father's．（ ）
A．I meanB．That is to say
C．Above allD．Believe it or not
The second C919 large passenger plane its first flight at Shanghai Pudong International Airport on December 17th， 2017．（ ）
A．completesB．completed
C．has completedD．was completing
The traffic is terribly busy in the morning． You'd better avoid in the center of the city．（ ）
A．driveB．drivingC．to driveD．driven
High﹣speed railways have developed rapidly in our country． Today China has high﹣speed rail network（铁路网） among all the countries in the world．（ ）
A．longB．longer
C．the longerD．the longest
China's star skater Wu Dajing won the gold in the men's 500 meters in Pyeong Chang Winter Olympic Games， setting a world record time of 39.584 seconds．
exciting news it is! Let's give him the thumbs﹣up（点赞）!（ ）
A．WhatB．What anC．HowD．How an
Be quick， we'll fail to catch the school bus．
Don't worry． It's only seven o'clock now． We still have enough time．（ ）
A．andB．butC．orD．so