以下可以调节混凝土中空气含量的外加剂是（）。
A.减水剂
B.加气剂
C.引气剂
D.消泡剂
参考答案：B, C, D
There existed an obvious________ between the accounts of the witnesses, so a judgment was not announced in court.
A．conception
B．conflict
C．authority
D．restriction
下列哪些NHL病人可考虑以放疗为主
A．低度恶性组临床分期Ⅰ期
B．中度恶性组病理分期Ⅰ期
C．高度恶性组病理分期Ⅰ期
D．低度恶性组临床分期Ⅱ期
