14C的放射性可用于考古断代。下列关于14C的说法中正确的是( ) A.质量数为6 B.质子数为6 C.电子数为14 D.中子数为14 答案:【答案】B 【解析】14C中含有的质子数为6,质量数为14,根据质量数=质子数+中子数可知,14C中含有的中子数=质量数-质子数=14-6=8,核外电子数=质子数=6。
The living room is clean and tidy, with a dining table already _______ for a meal to be cooked.
[ ]
A.
to lay
B.
laying
C.
laid
D.
being laid