adj.更困難的

形容詞tough的比較級.

Humans have the tougher time ascending in harmlessness as compared with dolphins and whales. 相比海豚和鯨魚，人類在提升入無害中有著更困難的時期。

But as climate change causes plants to peak earlier, caribou newborns that eat the plants face tougher odds for survival. 但是當(dāng)氣候變化的原因植物高峰前，北美馴鹿新生兒吃植物面對更困難的機(jī)率為了生存。