①将花蕾在酒精中浸泡约30s
②放入氯化汞液中2~4 min
③无菌水清洗,然后用吸水纸吸干花蕾表面的水分
④用无菌水冲洗3~5次
A:①②③④
B:①③②④
C:③①④②
D:②③①④
—They moved here soon after their son was born.