The old couple decided to ____ a boy and a girl though they had three children of their own.
The time and effort he has devoted during the past few years ______ trees in that remote area is now considered to be of great value.
.The child broke his father’s favourite vase; Although knowing he would ____ to be punished, he told his father the truth.
Children should be instructed to put things _____ they belong in their early childhood.
______ label to each of the trees, with detailed introduction of their features, and visitors will know more about them and how to protect them.
With ________ word “PM 2.5” repeatedly appearing in ________ media reports, the public can’t help wondering what it really means.