Thisriverissobigthatitisimpossibletobuilda_______underitwithoutmoderntechnology.
A、canalItisnot---_______formetoreturnallthebookstothelibrarynowbecauseIstillneedsomeofthemformyresearch.
Theengineersinthislabspentseveralweeks_______theirplansforthenewbicycle.
John_______tobeapoliteman.Butinfactheisveryrude.
Sometimesitisverydifficultto_______someoftheEnglishwords.Eventhenativespeakercannothelp.
Somelazymenwouldrather_______thanwork.
