_____we keep the window _____ all the time—No, you don’t have to .

Does Helen speak English ____—Yes. Her English is very ____.

for the breakdown of the school computer network,Alice was in low spirits.

依次填入下列横线处的词语，最恰当的一组是（ ）研究伊始，该团队选取了华北、西北地区生产的几十种马铃薯进行分析 ，从营养成分、 硬度等方面多次试验， 确定了适合加工马铃薯面条的两个品种。随后，又从诸多面粉种类中试验选取了 的小麦粉加以调试。

If you _____________ your study, I am sure you will make greater progress.