Because of the Russian gas limit to Europe, attempts _______ to use botanical fuel as a source of power.
The effect a teacher has _______ children may be greater than that of their parents.
—Everyone in my class passed the exam.—Oh, really? It ________ difficult.
I ran across David while walking along the street yesterday. I ________ him for three years.
—You are required by law _______ seat belts.—Thanks for your reminding. I’ll do it right away.
______ such a heavy loss in the earthquake, they got help from all over the world.