-- Have you ever been to Shanghai, Mary? -- Yes. I _______ there for three clays with my parents last month.
The light bulb ______ by Edison in the middle of the 1780s.
The old scientist has made a great contribution the moon.
—What is the table made _______?—Wood.
Many countries have a lot of rockets into space.
—How can I learn English well?—You will learn it well ________ you practice speaking it often.