Many types of rock are （）from volcanoes as solid, fragmentary material.

单项选择题He raised his eyebrows and stuck his head forward and （）it in a single nod, a gesture boys used then for O. K. when they were pleased.

A．shrugged
B．tugged
C．jerked
D．twisted

单项选择题The ball （）two or three times before rolling down the slope.

A．swayed
B．bounced
C．hopped
D．darted