题干
Many people ________ their friends or family by mobile phone today.
A：keep in touch with
B：get on with
C：catch up with
答案(点此获取答案解析）
A
Many people ________ their friends or family by mobile phone today.
A：keep in touch with
B：get on with
C：catch up with
元素，其中甲、乙两元素原子的最外层电子数分别是次外层电子数的2倍和3倍，丙元素原子K层和M层电子数之和与L层的电子数相同．下列判断不正确的是（ ）