从每题所给的A、B、C、D四个选项中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
21. In _____ world of uncertain energy prices, light rail looks like___ smart choice.
A. the, the B. /, a C. a, a D. a, the
22. ----Why doesn’t he turn up yet? It’s almost time for meeting.
---- It’s no ________ that he didn’t come.
A. difference B. importance C. relation D. matter
