这几年城市的变化太大了，我都快认不出来了。

zhè jǐ nián chéngshì de biànhuà tài dà le, wǒ dōu kuài rèn bù chūlái le.

The city has changed so much in recent years that I can barely recognize it anymore.

气候变化是全球面临的严峻挑战。

qìhòu biànhuà shì quánqiú miànlín de yánjùn tiǎozhàn.

Climate change is a severe challenge facing the entire world.

她注意到了他态度上的微妙变化。

tā zhùyì dào le tā tàidù shàng de wéimiào biànhuà.

She noticed a subtle change in his attitude.