Yī ge rén zài yìguó-tāxiāng, nánmiǎn huì juéde gūdān.
Living alone in a foreign country, it's hard not to feel lonely.
Tips
usage
孤单 emphasizes the emotional feeling of loneliness, while 孤独 can be more philosophical or profound - being fundamentally alone. 孤单 is what you feel on a Friday night with no plans; 孤独 is an existential state.
