切花冷藏是延长切花寿命的主要方法,红掌、姜花、赫蕉、万代兰等冷藏最适温度是()。
A.1℃
B.13℃
C.4℃
D.8℃
参考答案:B
有一台直流电动机,其输入功率为6千瓦,输出功率为5千瓦,则该电机的效率(),损耗()。
A、100%,1千瓦
B、83%,1千瓦
C、100%,2千瓦
D、90%,2千瓦
句型转换。(共5小题;每空1分,满分10分)
小题1:I have many books in the bag.(改为同义句)
many books in my bag.
小题2:Lucy has one crayon in her pencil case.(对划线部分提问)
How many crayons Lucy in her pencil case?
小题3: There are some birds in the tree.(改为否定句)
There birds in the tree.
小题4:That is my dictionary,(改为复数)
are my .
小题5:My parents travel to Beijing by train now.(对划线部分提问)
your parents travel to Beijing now?