短语讲解：
1. Efforts to develop a malaria vaccine have so far been disappointing, so programs to control the disease have focused on preventing transmission of the parasite.
so far到目前为止；迄今为止；到这点为止
例句：So far, so good.
到目前为止, 一切顺利。
focus on致力于
例句：He focused his mind on his lessons.
他把心思集中在功课上。
2. That has been happening with current mosquito-killers, including chemicals known as pyrethroids.
known as以…知名；被认为是
例句：This property is known as ductility.
这个性能叫做延展性。
3. When we think about a large-scale goal to take on malaria, it's not an either-or situation.
think about考虑…; 捉摸…
例句：Elinor is thinking about emigrating to the United States.
埃莉诺正在考虑移居美国。
take on披上，穿上，戴上；呈现(面貌等)；具有(某种性质、特征等)
例句：The campus has taken on a new look.
校园换了新貌。
4. We're going to have to throw multiple things out there in order to see what the optimal combination is to achieve control
throw out拒绝; 否决; 提出(暗示、建议等)
例句：The suggestion was made at the conference, but they threw it out.
这个建议在会上提出来了, 但他们不予考虑。
in order to为了
例句：We started early in order to arrive before dark.
为了在天黑前到达,我们很早就动身了。
5. It is widely used for insect control against a wide variety of pests.
use for作…用
例句：We used the seal's fur for coats.
我们用海豹皮做大衣。
a variety of多种的
例句：This shop sells a variety of toys.
这家商店出售各种各样的玩具。
