In that school, English is compulsory for all students, but French and Russian are___
Just as a famous Chinese saying goes, a timely heavy snow is a ______ of good harvest next year.
Those black clouds are a sure _____ that it’s going to rain.
She raised her finger to her lips as _____ for silence.
Shortly after the accident, _____ police were sent to the spot to keep order.
We already have ______ pencils, but we need two ______ pens.