=()。
A.A
B.B
C.C
D.D
参考答案:C
An emergency sea anchor may be constructed by using().
A.a boat bucket
B.an air tank filled with water
C.an oar and canvas weighted down
D.All of the above
澳大利亚的大堡礁属于()
①玄武岩
②大理岩
③沉积岩
④石灰岩
A.①③
B.②③
C.③④
D.②③④