He didn't know anything. He wishes I (let) him know earlier.
He didn't know anything. He wishes I (let) ______ him know earlier.
Đáp án: had let
Giải thích: Câu ước ở quá khứ: S + wish(es) + S + had Vp2
Dịch: Anh ấy không biết gì cả. Anh ấy ước tôi cho anh ấy biết sớm hơn/