21．She should have offered to pay---- ________, she is a millionaire.
A．after all B．above all C．in all D．at all
22．When a pencil is partly in a glass of water, it seems as if it ________.
A．breaks B．has broken C．were broken D．had been broken
23．A bridge _____________ in the distance and its construction _____________ in a year.
A．is being built; will be finished B．is built; has been finished
C．has been built; is being finished D．is being built; is finished
