It was _____ he came back from Africa that year _____ he met the girl he’d like to marry.

A．when; then

B．not until; that

C．only; when

D．not; until

下列各组原子和离子半径变化的顺序中，不正确的一组是( )。

A．P^3-＞S^2-＞Cl^-＞F^-
B．K⁺＞Ca²⁺＞Fe²⁺＞Ni²⁺
C．Al＞Si＞Mg＞Ca
D．V＞V²⁺＞V³⁺＞V⁴⁺