第18题: [单项选择]The development of the light bulb __ partly as a result of the widespread availability of electricity and the need for cheap, cicada light. A. occurring B. was occurring C. was occurred D. occurred 参考答案:D 答案解析:考的是语态和时态。讲的是过去的事情,用一般过去时。Development的出现或发生,可用主动态。选项D是正确的。