They found that the sick plants could “sneeze” and 23 tiny water drops filled with leaf rust germs, spreading the disease to neighboring plants.
答案：(A) shoot out
【句型】shoot out 固定片語「噴射出」，表示生病的植物會「打噴嚏」並噴出帶有病菌的小水滴；hold on（抓住不放）、come across（偶然遇到）、give up（放棄）都不合。
shoot 你腦中的畫面幾乎都是「射擊、開槍」，所以用在植物身上會覺得突兀。shoot 的核心概念其實是「快速而有力地移動或射出」，槍只是其中一種情境。shoot out 就是噴射而出、迅速射出——水滴從葉子上彈出去，正是這個動作。
空格前後把畫面講得很清楚：the sick plants could "sneeze" and ___ tiny water drops filled with leaf rust germs（生病的植物會「打噴嚏」，並 ___ 帶著銹病病菌的小水滴）。sneeze（打噴嚏）這個動詞已經把答案框住了——打噴嚏就是把東西快速噴出去。再往後 spreading the disease to neighboring plants（把病傳給鄰近植物），也需要水滴確實離開葉面才成立。
hold on（抓住不放；電話別掛）方向完全相反，水滴要出去不是留下；come across（偶然遇到；給人某種印象）的受詞是人或想法，不是水滴；give up（放棄）語意不通。
shoot out（噴射而出）、shoot up（迅速上升、暴漲；植物抽高）、hold on（抓住不放；稍等）、come across（偶然遇到）、give up（放棄）、be filled with（充滿……）。
When a person sneezes, the droplets can spread diseases. Now research shows that plants have a somewhat 21 problem. Plant diseases can also spread through tiny water drops that jump off leaves— a plant's version of a sneeze. Scientists already knew earlier that wind and splashes of rainwater can move bacteria and other germs from leaf to leaf.
22 other possible transmission routes, researchers at Virginia Tech observed water drops on the leaves of wheat plants that were infected with leaf rust. They found that the sick plants could "sneeze" and 23 tiny water drops filled with leaf rust germs, spreading the disease to neighboring plants. The researchers noticed that small drops of water on the wheat leaves would move to combine and form a larger drop. As they were moving, the energy of the droplets in motion would be released. This energy allowed the water 24 into the air, which looked just like sneezing!
However, not all plants can sneeze. The ability is 25 to those with leaves that are hydrophobic, or repel water—a special feature that forces the liquid to move away when the leaf is exposed to it.