【题目】To be an excellent runner, you must be prepared to go through much hard work.
A.for a start
B.at the first
C.with a start
D.at last

【答案】A
【解析】A. for a start首先；B. at the first一般要加名词构成短语；C. with a start惊动地；D. at last最后；句意：为了成为一名出色的运动员, 首先, 你必须准备好经历很多的艰苦训练。根据句意，故选A。