The teaching building is _________ by many trees, some ______ over 30 metres.
—What a mistake! —Yes. I________his doing it another way, but without success.
________students are required to take part in the boat race.
The dog was approaching ________the garden when she ran out.
They have________signs in some places to remind (提醒)the visitors not to step on the grass.
The cities' bright lights,theatres,films,etc.are________.