There have been many comparisons (比较) made between London Underground and New York Subway. They are the best known public transport systems (公共交通运输系统) in the world and each is a key part of one of the greatest cities of the world. The two systems have many things in common(相同), including their ages and fame（名声）, but there are also important differences.

    The following table shows some of the similarities (类似）and differences.

记不等式组$\left\{\begin{array}{c}x\ge 0\\ x+3y\ge 4\\ 3x+y\le 4\end{array}\right.$所表示的平面区域为D．若直线y=a（x+1）与D有公共点，则a的取值范围是____ ．

下列首都中被誉为“花园城市”的是（     ）。