我和肯和奥尔加坐在一起看太阳下山。

I sat with Ken and Olga and watched the sun ___go ___down.

傍晚时分我们可以去海滩看太阳下山。

Late in the evening we can go to the beach and see the sun ___go ___down.

太阳下山时，天空变成橙色。

As the sun ___goes ___down, the sky turns orange.