题目

阅读下面的短文，用括号内所给词的适当形式填空，必要时可加助动词。Think before we speak!It was a sunny and enjoyable day. Everyone in the railway station was waiting for the train【1】(arrive). Among the crowd, there was a group of young friends who were on board for vacation.It was a busy station with a lot of people and some juice shops, coffee and tea stalls, newspaper shops, etc. The train was arriving and everyone prepared to get into the train to their seats.The group of friends made loud noise【2】(welcome) the train as it moved into the station. They r双曲线的渐近线方程是2x±y＝0，则其离心率为(  )A．5 B． C． D．