如图，在 ▱ ABCD 中，点 E ， F 在对角线 AC 上，且 AE = CF ．求证：
（1） DE = BF ；
（2）四边形 DEBF 是平行四边形．
The little boy was so careless with his spelling that he often________letters from words.
Many factories and banks in some countries have closed down as a direct________of the financial crisis worldwide.
－Water is the most precious resource in the world. －So the government________every one of us to save water.
We can hardly imagine Tom________the heavy task in a single day.
The man was quite________of the danger；he had no choice but to face it.
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