【单选题】Most publishing is now'electronic'in the sense that books, magazines, and newspapers are prepared on computers, and exist as computer files before they are printed on paper. Often there are advantages...
A.
Readers will have more accesses.
B.
Books and newspapers will be kept as computer files.
C.
It will not make any sense to keep the printed versions.
D.
Electronic publications will replace printed ones.
【简答题】Diagram the outer-shell electronic structures of P and F. Indicate how bonding occurs between P and F to give PF 3 . What molecular shape would you expect?