Chọn và điền dạng đúng của các động từ cho sẵn.

be disagree do include know look see seem understand

Ancient aviators?

Everyone (1) __________ that humans have been flying for only a few hundred years. But (2) _________ it possible that ancient civilizations also had the ability and technology to fly?

In the Nazcan Desert in southern Peru, there are hundreds of lines which an ancient culture drew in the dust. On the ground, they just (3) __________ like straight lines. But when you (4) __________ them from the air, you (5) __________ exactly what they are. They are incredible and enormous pictures. The pictures (6) __________ animals, birds and symbols.

One bizarre theory, which most mainstream scientists (7) __________ with, is that the people who made the lines thousands and thousands of years ago flew above the lines in balloons. It (8) __________ incredible, but a few people (9) __________ believe it’s possible.

Thêm dấu phẩy vào chỗ cần thiết (mệnh đề quan hệ không xác định).