This is an exercise that will help you learn the differences between frequently confused words. We call them "Appropriate Words" sentence completion exercises because the key thing to learn here is the appropriate context in which you should use these words. Sometimes you can use both words, but one answer is more appropriate to use in that context. For other sentences, one word is the only possible answer. The explanations at the bottom of each page will clarify all of the answers if you're not sure about certain sentences.
An explanation of the answers:
1. Although the difference between videos and movies may seem hard to understand at first, it's quite simple, in fact. Video is the general word for any moving picture. It can describe a short recording of a cat on YouTube or a complicated drama between actors. A movie, on the other hand, is a video with a story. It's usually longer and fictional--though not always. Since Hollywood is known for making movies for the cinema, "movies" is the correct answer for number 1.
2. Mow and cut are also similar. The easiest way to describe the difference between them is that cut can be used for anything--cut the hair, cut the paper, etc. Mow is specific. Mow means to cut grass. Since a lawn is made out of grass, "mow" is the more appropriate word here.
3. Many English learners have a hard time differentiating between see and watch. The difference lies in the fact that "see" is what you do when your eyes are open. It is a passive act. On the other hand, "watch" means to see something, but to also pay attention to it, often for a longer period of time. Since this sentence is about generally being able to observe the stars in the sky due to a lack of light pollution, "see" is the correct answer here.
4. A ditch is a small trench or rut in the ground. It is usually used to drain water. Because it's small and usually made by people, a river wouldn't run through a ditch. However, rivers can, and usually do, run through valleys--the low point between two hills or mountains.
5. To flee something (the past tense of flee is fled, by the way) is to run away from it. To evacuate something means to empty it. It's usually used in the passive voice. For example: The city was evacuated before the storm. Since number 5 is written in the passive voice and is about emptying a building, "evacuate" is the correct answer here.
6. Number 6 is about a recording of a recent event--a tornado. Because there is no plot to this recording, it is not technically a movie. Therefore, video is the correct answer here.
7. Remember, to mow means to cut grass. Since hair is not grass, obviously, "cut" is the correct answer.
8. People usually pay attention to the TV when they are viewing a program. This means that "watch" is the more appropriate word to use in number 8.
9. Unless the road referred to in number 9 is on the crest of a ridge, "ditch" is the better choice for the answer here. Usually, ditches are intentionally dug on the sides of roads to ensure that water does not collect on the road surface.
10. Since people are running away from a burning building in number 10, "fleeing" is the correct answer here.