800 câu trắc nghiệm Điền từ Tiếng Anh có đáp án - Phần 22

The Olympics are also an opportunity to invest in projects (5)_____ improve the city’s quality of life, such as new transportation systems

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The Olympics are also an opportunity to invest in projects (5)_____ improve the city’s quality of life, such as new transportation systems

who

which

what

whom

Giải thích

B là đáp án đúng