律诗分为____、____、____、____ 四联。
首联 颔联 颈联 尾联
将一枚硬币连掷三次，出现“2个正面，1个反面”的概率是 ▲ ．
The baseball is the table, the floor. [ ]
A. on, under
B. on, in
C. under, on
D. under, under
