监测设备的检查、校验和检定应做好记录,并妥善保存,保存期至少()年。
A.0.5;
B.1;
C.1.5;
D.2。
参考答案:B
-What are you doing?
-I'm some cards for my friends. [ ]
A.make
B.making
C.to make
D.makes
我国儿童出生时平均头围约
A.30cm
B.34cm
C.44cm
D.46cm
E.50cm