TheBentPyramidoutsideCairo__________ancientEgypt’sfirstattempttobuildasmooth-sidedpyramid.
The____populatedareawasabreedingplaceforinfectiousdiseases.
Thefirststepinthestudyofanylanguageisobservingand____preciselywhathappenswhennativespeakersspeakit.
Marytiptoedoverandtooktheclockawaybecauseshehatedtohearit（）whenshewastryingtogotosleep.