catch the sun略微被晒黑；被阳光照亮
Her face had definitely caught the sun. 她的脸绝对被晒黑了。

a place in the sun显要地位；有利位置
Only the most vigorous will win their place in the sun. 只有最具活力的才能抢占有利位置。

under the sun;beneath the sun天底下；世上；到底；究竟
Nobody under the sun eats more than you do. 普天之下没有人吃得比你多。

sun yourself晒太阳
She was sunning herself in a riverside park. 她在河滨公园晒太阳。

太阳从东方升起。
误 A sun rises in the east.
正 The sun rises in the east.
解析：像sun这样世界上独一无二的自然物前须用定冠词the。只有在sun前有形容词修饰时才可加不定冠词a,起描绘作用。