The little boy was so careless with his spelling that he often________letters from words.
The natural resources, such as mine, forest, and hydropower (水电)in that area have been __________.
The matter __________ to our study requires __________ with carefully.
Dogs have a very good __________ of smell and are often used to search for survivors in an earthquake.
They found themselves in front of a wooden house __________ with bamboos.
What do you mean, there are only ten tickets? There __________ be twelve.