As there is less and less coal and oil, scientists are exploring new ways of making use of ______ energy, such as sunlight, wind and water for power and fuel.
In the students’ eyes, Mrs Smith is a mother more than a teacher. she treats the students just like her own children.
This morning I picked up wallet in surprise on my way to school.
—Would you like to come to the party?—______, but I’m very busy preparing for the exam.
—The weather report says it is going to be a fine day.—But I will take an umbrella with me ______ rain.
A nest is to a bird ______ a house is to a man.