我有几道问题相问问兄弟姐妹们，谢啦！！！

violetsapphire

The capital of United States, originally New York City,was moved to Philadelphia (where stayed) until 1800.

为什么括号里的是错误的？

The strength,size and surefootedness of the llama make it (excellent) beast of burden in mountainous region today as it was in the past.

为什么括号里的是错误的？

谢谢各位帮我的大哥大姐们！！！！

waterfrog

an excellent