题目

Washington D.C. is the capital of America, _________ it is smaller than New York.           A. so          B. but         C. and          D. or 答案：B20．解不等式组$\left\{\begin{array}{l}{1-3（x-1）＜8-x}\\{\frac{x-3}{2}+3≥x+1}\end{array}\right.$，并在数轴上表示出其解集．