Great changes _______ in our country since 1990.

A．were taken place

B．took place

C．have taken place

D．have been taken place

股市有风险，投资须谨慎。成千上万的股民同台博弈，结果必然是有人欢喜有人愁。

“股市有风险”所指的“风险”属于（）。

A．信用风险

B．法律风险

C．投资风险

D．违约风险