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
