题干
It was with great joy _______ he received the news ____ his lost son would soon return home.
A：because; that
B：that; that
C：because; which
D：that; \
答案(点此获取答案解析）
B
B（g）+ 2C（g），且达到平衡。当升高温度时，气体的密度增大，则下列叙述中正确的是（ ）