在钢筋混凝土构件代号中,“TL”是表示( )。
A.连系梁
B.天沟板
C.楼梯梁
D.托架
参考答案:C
下列计算正确的是( )
A.a+a=2a2
B.a2•a=2a3
C.(-ab)2=ab2
D.(2a)2÷a=4a
The teacher propose that Jack ___ maths or physics instead of English because he was quick at numbers.
A.must study
B.could study
C.studied
D.study