沉默表明他对这个话题不感兴趣。

MaryacceptedDavids___(invite)tojoinhimforlunch.

Whenwereturnedfromourvacation,ournextdoorneighborswere______anewgaragebuilt.

Itisessentialthatyou__________anydocumentcarefullybeforesigningit.

Therediscoveryofthisspeciesofbirdsisoneofthemost___(ordinary)scientificfindingsinrecentyears.