28. They can’t decide who to go to the performance first.
29. Children have no idea where to eat lunch and dinner if they have extra classes after schooltime.
30. His mom doesn’t know when to pick him up after his class’ performance.
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wh- to V là cách dùng để rút gọn mệnh đề quan hệ thay vì sử dụng cụm chủ ngữ + vị ngữ