根据中文意思完成句子。
①我学英语已经有5年了。    

I ____ English for five years.
②在保护动物方面还有很长的路要走。
This is still ____ to go to save the animals.
③他妈妈生病了，他得在家照顾她。
His mother is ill, he has to ____ her mother at home.
④我们究竟能做什么？      

What ____ can we do?
⑤他在世界各地举办过音乐会。 He has given concerts____ the world.