Hi SallyLi,
According to me, usage of however in verbal section, especially sentence correction, means however only (you can spot the same meaning in any official example). But the same might not apply to RC.
Government policy has placed a priority on reducing inflation, but these efforts have nevertheless caused unemployment to increase.
In the above sentence, usage of but indicates contrast and usage of nevertheless after main verb in the second clause might conveys to show 'anyhow'.
Government policy has placed a priority on reducing inflation, but these efforts have (nevertheless) anyhow caused unemployment to increase.
Let's wait for expert's insight on the same.
Regards,
Raxit T.