21．______ two pandas from Chinese mainland have become ______ hot topic in Taiwan．
A．The; a B．A; a C．/; the D．The; /
22．It turns out that a house made of wood or bamboo may stay up in an earthquake while _____
made of steel may fall dowm ．
A．this B．one C．it D．what
23．The employees have not been paid ____ since the new manager took over this company last month．
A．regularly B．commonly C．absolutely D．ordinarily
