The water dark and dirty. It's no longer safe to drink.
A：became
B：has become
C：will become
D：was becoming
补写出下列句子中的空缺部分。
根据要求作文。
带着一颗心，锁定目的地，执着地前行；尽情享受沿途的风景，哪怕山高路远，哪怕日晒雨淋……
以“向目的地进发”为题写一篇文章。
要求：（1）将题目抄写在答题纸上；（2）不限文体（诗歌除外）；（3）不少于600字；（4）文中不出现含有个人信息的地名、校名和人名等。
It was ______ fine weather that they ________ went swimming.
