Hi, Rob~! I like 喜洋洋与灰太狼 too~ I think it better that if you could tell me the name of song, then I could find it for you.

我在努力地理解你说的话，请说慢一点。 I am trying to understand you. Please speak a little slower. 我努力地学习汉语，但是汉语太复杂了。 I tried to learn Chinese but it is really complicated. 他努力地想要去爱他的妻子，但是他做不到。 He tried to love he wife but he couldn’t. 她在努力学习游泳。 She is trying to learn to swim. I think there is no big problems in your Chinese sentences. but just for the use of 了。It can be use for the meaning of the past time, but usully we put it after a verb or a adjective, expressing that something somebody have already done. e.g.: 我做完作业了。I have finished my homwork. 我从北京回来了。I have been back from Beijing. 我很努力地学习了魔术，但是依然做不好。I learned magic tricks very hard, but still can not do it well.

If you want to ask where something is located you can say: sth 在哪儿（在哪里，means where）？ 例：你家在哪儿？Where is your home? (Question) This is correct. But how do I say I don’t know where something is located? 我不知道在哪儿地铁。（this is wrong.）I don’t know where the subway is. (Statement) This one you should say: 我不知道地铁在哪儿。 I think you could use 在哪儿 easily in this pattern. eg: something 在哪儿 or 在哪里？ or 我不知道something在哪里。You could change something into what you want to change. like museum博物馆, supermarket超市, park公园 etc. You could change something into what ever little places or big places. For exmple: 1. 博物馆在哪里？ 2. 超市在哪里？ 3. 公园在哪里？ 1. 我不知道博物馆在哪里。 2. 我不知道超市在哪里。3. 我不知道公园在哪里。 Hope these can help you.

Of course, it's no doubt that it is quite beautiful.