______ the price of gas is starting to come down, many people are choosing to take the bus or the train instead.
It’s no use ______ without taking action.
Sarah pretended to be cheerful, ______ nothing about the argument.
The lecture, ______ at 7:00 pm last night, was followed by an observation of the moon with telescopes.
Marco Polo is said to have sailed on ______ Pacific Ocean on his way to Java in ______ thirteenth century.
The other scientists ______ to her ideas with a mixture of criticism and silence.