根据句意，用所给动词的适当形式填空。
(1)By the time he left college, he ____ (get) much working experience because of his part-time job.
(2)John, like other children who have no parents,____  (take) good care of in our country.
(3)We should wash hands properly ____  (fight) against H7N9 virus.
(4)Look! There are so many kites____ (fly) in the sky.
(5)If you want to improve your English, you should practice____ (speak) it as much as possible in and out of class.

“他们绕东南亚航行到印度，有些船继续西航到亚丁和波斯湾口，而个别船则驶入非洲东岸的一些港口。我们应该记得，在这一时期，葡萄牙人只是刚刚开始沿非洲海岸探寻航路。”“他们”是指谁率领的船队（   ）