高速柴油机用柴油的十六烷值一般不应低于50。
参考答案:错
先化简,再求值:(a-1)(a+2)-a(a-1),其中a=3.
If ______ in wet sand, the vegetables can ______ fresh for a long time.
A.being buried; remain
B.buried; remain
C.buried; be remained
D.burying; remain