这两句话意思完全相反，你看清楚了吗？

Zhè liǎng jù huà yìsi wánquán xiāngfǎn, nǐ kàn qīngchu le ma?

These two sentences have completely opposite meanings; did you look carefully?

他不同意这个计划，意见正好相反。

Tā bù tóngyì zhège jìhuà, yìjiàn zhènghǎo xiāngfǎn.

He doesn’t agree with this plan; his opinion is exactly the opposite.