As there is less and less coal and oil, scientists are exploring new ways of making use of ________ energy, such as sunlight, wind and water for power and fuel. [ ]

A. primary  

B. alternative

C. instant  

D. unique

练习者两腿前后分开，逐渐下劈成一直线，两手左右扶地，做上下振压运动或做静压腿，称为（）。

A.正压腿

B.竖劈叉

C.后压腿

D.弓步压腿