根据句意，用括号内所给单词的适当形式填空。【小题1】His father lookedangrily (angry)at his son. Because he often mak

根据句意，用括号内所给单词的适当形式填空。
【小题1】His father lookedangrily (angry)at his son. Because he often makes mistakes.
【小题2】Next Sunday will be my brother’s ninth ( nine ) birthday.
【小题3】The children are very happy. They can’t hide theirexcitement (excite)
【小题4】Luckily (luck), he found his lost pen just now.
【小题5】The swallow flies tonorthern (north) countries in summer every year.
【小题6】Some people think learning English isuseless (use).That’s wrong.

解析：【小题1】考查副词的用法。修饰look at短语，应该用副词。angry的副词形式是angrily。故填angrily。【小题2】考查序数词。“九岁生日”是ninth birthday。故填ninth。【小题3】考查物主代词的用法。形容词性物主代词their后跟名词。故填excitement。【小题4】考查副词。修饰整个句子，用副词。lucky的副词形式是luckily。故填Luckily。【小题5】考查词性转换。north“北方”；northern“北方的”，后加名词。故填northern。【小题6】考查形容词作表语。根据句意可知，应该用useless“无用的”。故填useless。

就是这个解释