China’s high-speed railways(中国高铁)________ rapidly during the past few years. Now many foreign countries invite them to make contributions to building up their homelands.A. have developedB. developedC. develop
______, is this your eraser?
What’s this ________?
---Hello, Mary. This is Joe. ---_____________.---Nice to meet you, too.
This time I want to do ____________.
— How long are you staying there? —____________.