误 She is at a poor state of health.
正 She is in a poor state of health.
析 state作“状态”“状况”解时,常用于be in a state of sth 的结构,表示“处于某种状况〔情况〕”,这里介词用in,不用at。
误 The head of the state played a key role in politics.
正 The head of state played a key role in politics.
析 用head of state表示“国家元首”时, state前不加冠词。
误 The United States are located in North America.
正 The United States is located in North America.