阅读下面短文，根据文章大意用所给单词的适当形式填空(未提供单词的，限填—词)，使文章意思完整，正确。
There once lived a king and a queen. They were very stupid. One day the queen had a baby daughter. When they saw their baby, they both cried out, "My goodness! ____ small it is! It's hairless and toothless! It's a monster (怪物)!" They ____ (send) for all the doctors in the country and ordered them ____ (make) some medicine for her.
"After she takes your medicine, she must grow to the right size and have hair and ____ (tooth)," the king said to the doctors. "If you don't do this, I ____ (kill) you." The doctors thought it was not possible, ____ they could not say anything against the king's order. Just then an old doctor came up. "Oh, we shall ____ (certain) follow your order," he said, "but it takes time. We have to dig for something to make medicine in the Kunlun Mountains when the snow melts for the ____ (two) time. The snow on the mountains melts only once in six years. So we need twelve years."
At last the king agreed and the doctors took away the little baby. ____ her twelfth birthday, they brought her back to her parents with long black hair and beautiful teeth. The king and queen felt very ____ (satisfy) and gave the doctors many expensive presents.
叶表皮细胞装片，在视野中能清晰地看到细胞壁和细胞核，但看不清液泡。下列操作能帮助看清液泡的是