Eye doctors recommend that a child's first eye exam ________ at the age of six months old.
It's a custom in China to have some tea or other drinks before the meal ________.
—What’s all that noise about outside?—Oh, I forgot to tell you. The road to the railway station ______.
Since the time humankind started gardening, we _____to make our environment more beautiful.
We won’t start the work until all the preparations __________.
Sofia looked around at all the faces: she had the impression that she _____ most of the guests before.