从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。
21．I prefer a flat in Inverness to ______ in Perth, because I want to live near my school.
A．one B．that C．it D．this
22．The get-together has to be ______ because Selina has to _________ her grandmother’s.
A．called in, called on B．called off, called on
C．called off, called at D．called up, called at
