这种黑咖啡比普通咖啡更苦。

This black coffee is ___more bitter than regular coffee.

谈判失败后，他的言辞变得更为尖刻。

After the negotiation failed, his words became ___more bitter.

今天的风比昨天更刺骨。

The wind today is ___bitter than yesterday.

失败后的失望比我们预想的更难承受。

The disappointment after failure was ___more bitter than we had expected.