已知集合U={1,3,5,9},A={1,3,9},B={1,9},则∁U(A∪B)=________.
{5}
易得A∪B=A={1,3,9},则∁U(A∪B)={5}.
The fire spread through the hotel very quickly but everyone_____get out.
A.had to
B.would
C.could
D.was able to
预应力钢束及粗钢筋在使用前必须作张拉、锚固试验,应进行()、喇叭,摩阻等预应力瞬时损失测试,以保证预施工应力准确。