I watched the plane go higher and higher until I lost _____ of it．

Young kids! You'd better apologize to us，or we________the right to accuse you of cheating.

As far as I’m concerned ,you should read more literature (著作)to enrich your _______.

Bending down，he        the footprints    that hadn’t been blow away in the wind, concluding that they belonged to a wolf.

It’s said that this kind of plant only gives off this strange perfume on ________ conditions which the scientists are trying to figure out now.