32.把……换成　 exchange … for

31.手工地　 by hand

30.相对论Theory of Relativity

29.努力避免失败try to avoid failure

28.试用思维策略

try using the thinking strategies

27.强迫某人做　 force sb to do

26.反复试验的结

a long process of trial and error

25.了解到 be aware of

24.与……相连be connected to

23.一系列不同的尝

a series of different attempts