Companies usually _____ a number

Companies usually _____ a number of experiments before a new product is launched．
A、practice
B、control
C、carry
D、conduct
【正确答案】：D
【题目解析】：此题考查词意辨析。Practice实践、练习，control控制，carry携带，conduct进行、实施。选项D是正确的。【句子大意】公司在新品上市之前通常要做大量的实验。