冬季建筑施工中,为了保证施工质量,常在浇注混凝土时加入盐类,其主要作用是( )
A. 增加混凝土的强度
B. 防止建筑物被腐蚀
C. 降低混凝土的固化温度
D. 吸收混凝土中的水分。
表面张力的影响因素有( )
A. (A)体系温度
B. (B)密度
C. (C)共存相的种类
D. (D)物质的种类
Read the following statements and then decide whether each of them is true or false based on the information in the text.1) Recently, the family had picnics and gatherings quite often under the pine tree in the park.
A. 对
B. 错
The writer occasionally visited the pine tree after her mother's death because she missed her mother.
A. 对
B. 错