Look at the children.They______(read)books in the reading room.

Look at the children.They______(read)books in the reading room.
Look at the children.They______(read)books in the reading room.

Look at the children.They______(read)books in the reading room.
Look at the children.They__are reading____(read)books in the reading room.
look 看到的应该是现在进行时,所以填are reading

Look at the children.They_are__reading___(read)books in the reading room.
瞧这些孩子，他们在阅览室读书。