Part I Vocabulary and Structure (20 points)Directions: In this part there are 20 incomplete sentences. For each sentence there are four choices marked A, B, C and D. Choose the ONE answer that best completes the sentence. Then mark the best choice and mark the corresponding letter on the Answer Sheet with a single line through the center.1. It is reported that a (n) _of accidents has occurred at that crossroads. A. series B. lot C. number D. amount2. If som