it’s ________bad manners to blow your nose at ______ table

(2013·山东卷)There is no simple answer，________is often the case in science.

great changes have taken place in ourcity in the last few years!— Indeed, many high buildingshave _______all over the city.

Visitors to the National Museum can avoid long lines at the ticket booths by purchasing tickets ____

_______ patient when you argue with someone who is not so reasonable.