Inertial navigation,---- a vital role in space exploration, employs devices called accelerometers to measure accelerations of spacecraft.
A. it plays
B. which plays
C. which it plays
D. in which plays
为什么说从资本主义向社会主义的过渡是一个长期的历史过程?
Larch and spruce trees ---- in bogs and wet areas of the northern United States.
A. found
B. are found
C. have found
D. finding
在凯恩斯主义出现后,财政政策不以实现收支平衡为目标,而是为实现充分就业服务。()
A. 对
B. 错