对于初次投入使用的制冷系统,压缩机累积运行()h,则应更换冷凝机油。
参考答案:300-400
鞋的尺码通常用“码”或“厘米”作单位,它们之间的换算关系是b=2a-10,(b表示码数,a表示厘米数),根据这个关系,小红的爸爸穿40码的皮鞋合______厘米,妈妈穿23.5厘米的皮鞋合______码.
请根据要求改写下列句子,每空一词。
1. We bought some books from the library last week. ( 改为一般疑问句)
Did you___ ____ ___ _____ books from the library last week?
2. Millie is 1.6 metres tall. Kitty is also 1.6 metres tall. ( 将两句和并成一句)
Millie is____ _____ tall_____ _____ Kitty.
3. I think this is a good way to keep healthy.( 改为否定句)
I ___ ____think this___ ____ a good way to keep healthy.
4. It took me two hours to finish my homework yesterday. ( 改为同义句)
I___________ two hours ___ ____ my homework yesterday.
5. Kate will return to China in a week. (对划线部分提问)
______ ______ will Kate return to China?