上海卷的词性转换题有个特点：从来不考生词，考的全是熟词的"亲戚"。decide 你认识，但空里要填 decision，你写得出来吗？拼写还不能错。下面这12个词族，是历年考得最勤的，每个我都把"最常被考的那个变形"标出来了。
动词变名词
decide → decision /dɪˈsɪʒn/ 决定
make a decision 是固定搭配。It's hard for him to make a decision.
invent → inventor / invention
人和物都要会：Edison was a great inventor, and the light bulb was his most famous invention. 看空格指"人"还是"东西"。
succeed → success → successful → successfully
一个词四副面孔，上海卷的心头好。He succeeded at last. / His success made everyone happy. / a successful man / She finished the task successfully. 填空前先判断词性，再动笔。
encourage → encouragement 鼓励
With the teacher's encouragement, she spoke louder.（在老师的鼓励下，她声音大了起来。）
形容词与名词互变
healthy → health
keep healthy 但 in good health。Eating vegetables is good for your health.
lucky → luck → luckily
luckily 放句首表示"幸运的是"，是词性转换里的高频答案。Luckily, nobody was hurt.
dangerous → danger
in danger 处于危险中。The animals are in danger. 注意 dangerous 拼写里只有一个 e 在 g 后面。
different → difference
make a difference 有影响、起作用。There is a big difference between the two photos.
able → ability
be able to do = 有能力做。His ability to solve problems surprised us all.
不规则变形，纯靠记
true → truth → truly
tell the truth 说实话。注意 truly 没有 e，very 多人写成 truely。
high → height /haɪt/ 高度
拼写大变样，ei 不是 ie。What's the height of the tower?
deep → depth 深度
同样变得面目全非。The depth of the lake is about ten metres.
考前建议：把这12组抄在一张纸上，只抄"原形→考得最多的变形"，贴在书桌前看三天，比反复刷题管用。你家孩子最常写错哪个变形？评论里报个词，我帮你看看怎么记。
