A $500 investment and a $1, 500 investment have a combined yearly return of 8.5 percent of the total of the two investments. If the $500 investment has a yearly return of 7 percent, what percent yearly return does the $1, 500 investment have ？（）

A.A

B.B

C.C

D.D

E.E

关于物质的潜热，说法正确的是（）。

A、物质没有相变化，升温时吸收的热量

B、物质没有相变化，降温时放出的热量

C、物质温度无变化，汽化时吸收的热量

D、物质温度无变化，冷凝时放出的热量