__________cleaning the yard and making up the beds for the old，we also read newspapers for them and had chats with them.

A．Except for

B．Rather than

C．Apart from

D．Instead of

枸橼酸盐试验阳性时，不应为（）

A.细菌生长pH不变

B.细菌生长产酸

C.细菌生长产碱

D.含溴麝香草酚蓝的培养基变蓝

E.细菌以枸橼酸盐为惟一碳源