How do you improve your listening, Mary? —Just ______ listening to tapes, it’s a good way, you know. [ ]

He made another wonderful discovery, ______ of great importance to science.

“How long does it take you ­________to Beijing?” “More than three hours.”

What can she do?—She can ______ Chinese kung fu.

─I want to know if your daughter will go to the teenager party. ─If your daughter does, so________.