---In order to keep ourselves safe, we should ___ the traffic rules. ---Yes. We shouldn’t cross the street when the lights are red. A. obey B. keep C. break
---_______ do people cut down so many trees here? --- To get enough space for a new road.
--- Red-crowned cranes need more people’s help. ---Yes. People working in the reserves are doing everything they can ____these birds.
---I often hear a new-born baby next door __________ a lot at night. ---Maybe the baby is hungry then.
About seventy percent of our earth _______ by water.
Today the forests are getting fewer and fewer. We must______ down too many trees.