問題詳情：
根據句意和漢語註釋，寫出單詞的正確形式。
uncle started to learn swimming in her __________(四十).
is now a manager while his twin brother___________(保持不變) a worker.
useful the ___________ sound! I think he will take them.(建議)
’t be too _________ about your son is old enough to look after himself.(擔心)
【回答】
1. forties 2. remains estions ied
知識點：單詞拼寫
題型：單詞拼寫
