The Great Barrier Reef, which is the world's largest coral reef system, __________ more than 50% of its coral cover, and experts predict that this could increase to 70% by 2050 due to climate change.

Kalimat di atas terdapat kata “could increase to 70% by 2050” yang menegaskan kalimat ini berpola present perfect tense. Present perfect tense harus diikuti dengan “has + V3”, maka opsi yang tepat untuk melengkapi kalimat di atas adalah “Has already lost”.Jawaban : B