All substances, _____ solids, liquids, or gases, are made up of entirely atoms.
_____has happened many times, children may get drowned in this river.
There is a mountain_____the top is always covered with snow.
The reason_____the manager explained at the meeting sounds reasonable.
I like to go shopping at the weekdays,_____the shop isn’t crowded.
The Science Museum,_____we visited during a recent trip to Britain, is one of London’s touristattractions.