A. sings B. is singing C. sang D. are singing

【題目】If the people obey the traffic rules, there will be fewer accidents. （改為同義句）
the traffic rules, there will be fewer accidents.

【題目】I think bicycles are much safer than other vehicles. （改為否定句）
I think bicycles much safer than other vehicles.

【題目】It is bad to spit in public. （改為同義句）
in public bad.

A. enough energy, healthy enough

B. enough energy, enough healthy

C. energy enough, healthily enough

D. energy enough, enough healthy

A. big enough; to live

B. big enough; to live in

C. enough big; live in

D. enough big; to live in it