It depends. when they have a plan to go back to US, 这个句子的意思是：they will go back to US .if they have a strong desire ( because of an urgent things happen ) to go back, then 这个句子的意思是：they want to go back to US.

Both^^ plz refer to the above n u need to say 她和她的丈夫要...... 她的=her 他的=his, or u can simply say 她和丈夫要......(coz it will be "her" husband anyway:P) U may refer to the following to use the word "要"： 动词 (要yao4 as Verb) 1. （希望得到 ） want; ask for; wish; desire eg: 各国人民都要和平。 All nations want peace. 2. （请求； 要求）ask [want] sb. to do sth.: eg: 他要我替他写封信。He asked me to write a letter for him. 3. （想要） want to; wish to: eg: 我还有几句话要说。I'd like to say a few more words. 他要学世界语。He wants to learn Esperanto. 4. （须要; 应该） must; should; it is necessary [imperative, essential] that...: eg: 我们要向模范工作者学习。We should learn from model workers. 5. （将要） shall; will; be going to: eg: 要下雨了。It is going to rain. 6. （需要） need; take: eg: 到那里要两个小时。It takes two hours to get there. 7. （表示估计， 用于比较） might; must: eg: 今天要比昨天冷。It might be colder today than yesterday.

To do something, and use to the word. Examples are: 1. I want to eat. 2 me to take a bath. 3. I'm going to play games. 4 I want to read

I agree with them, and I give you a match: they will go back to US = 他们将回去美国; they want to go back to US = 他们想回去美国 他们要回去美国 = they will go back to US (have plan or need to)

It could mean both, depending on what they emphasize here. If we are talking about what are they up to , we'd better translate the response "They will go back to.. " , iF we emphasize the destination is somewhere specific, not elsewhere, translating into " they want to go..." is better .