水泥砂浆面层如遇管线等,局部面层厚度减薄处在20mm以下时,必须采取防止开裂措施。( )
参考答案:错
He must stay at home to look after his ____ mother . She has been _____for a week.
A, ill . sick, B. sick ,ill C. ill ; ill D. sick ; illness
小儿初次感染结核菌至产生变态反应的时间是
A.48~72小时
B.4~6天
C.1~2周
D.2.5~3周
E.4~8周