人民币上学地理，依人民币上的景观完成下面小题．
要使（4x﹣a）（x+1）的积中不含有x的一次项，则a等于（ ）
从题中所给的A、B、C、D四个选项中选出与句中划线部分意义最接近的解释。
Jack called his mother at 7:30 yesterday, but she didn't pick up at that time.
