(    ) 16£®Her parents will come back ________________ two weeks£®
A£®after   B next   C£®in    D later
(    ) 17£®Things will get better in the future, we will have ______ cars and _______ pollution£®
A£®less, more    B£® Fewer£¬less  C£® more, more  D£®less, fewer
(    )18£®The boy is ______to go to school £®
A£® enough old    B£®  enough young   C£® old enough   D£®young enough
(    )19£®There are about five ____   young trees on the hill£®