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.
A：answer
B：speak
C：talk
D：ring
下列物质的化学式书写正确的是（ ）
人体中含量最多的金属元素是（ ）
