蘑菇属于大型真菌,它的地下菌丝的主要作用是: [ ]
A.吸收营养物质
B.吸收水分
C.吸收无机盐
D.固定地上部分
答案:A
A large crowd _______ wildly as the pilot _________ her plane safely in California.
A.had cheered; was landing
B.had cheered; landed
C.was cheering; had landed
D.was cheering; landed
焊件接阴极,焊条接阳极的接法称为正接法。