Since we have a focused subject ，we should not talk ________.
A、atonceD
译文：既然我们已经有了命题，我们就不应漫无边际地交谈。此题考查对固定短语的掌握情况。atonce立刻;athand在附近，在手头，即将发生;atintervals间或，不时;atrandom随便，任意。
Thisisthemostbeautifulvillage_______Ivisitedtheseyears.
Basically，theseattitudesamounttoabelief________leisurecanandshouldbeputtogooduse
Theyshouldtryto________theirusualinhibitionsandjoininthefun.
Theprofessorworkedfor7hoursata________.
Fishis________andexpensiveatthistimeoftheyearinthisarea.
