句型转换。

1．The students had great fun today．(改为否定句)

    The students____. great fun today.

2．We went to the park last Sunday．(就画线部分提问)

     ______  _______ you____last Sunday?

3．The beaches were fantastic．(就画线部分提问)

      _____ _____the beaches?

4.We found some boys on the playground. They were playing soccer．(合并为一句)

    We found some boys ____soccer on the playground．

5．She went to New York last summer．(就画线部分提问)

   _____ ______she ____to New York?

利用物标的初显距离和方位定位，观测船位精度差的主要原因是（）。

A．初显距离测定困难造成方位测定出现异时观测误差加大

B．初显距离测定困难，同时误差大

C．初显方位观测误差大

D．位置线夹角不好