题干
To them, the most important thing is _______make much money ______ get together.
A：not to, but
B：not, but
C：not, but to
D：not to, but to
答案(点此获取答案解析）
D
处，另一端与质量为m的小球相连，小球静止于P点。已知地面与半球形容器间的动摩擦因数为μ， OP与水平方向的夹角为θ＝30°．下列说法正确的是