1. complete the following sentences with the proper form of the given words. development, disappoint, explode, float, force, harmful, publish, solid, spread, surface, telescope, violent 1. the butterfly _____________ its wings and moved them slowly up and down . 2. that he failed the college entrance examination ______________his parents very much . 3. she found something unusual ____________on the __________of the river, which quite frightened her. 4. the famous writer ____________a lot of popular novels in that ____________firm. 5. with the ____________of our country’s economy, people's living standard has been greatly raised. 6. now that it's so warm, we can see fishes swimming on the ___________of the pool. 7. the ____________ of gravity makes things fall to earth. 8. with a __________ kick, the robber broke into the old man's house. 9. nothing can separate the two, because they have a ____________friendship foundation.
