"because they are very sweet" 可以用英文表示为 "because they're very sweet"。
这句话的来源是因为英语中有一个固定用法是在 "because" 后面接着一个缩写形式的 "they are"，即 "they're"。这样可以让句子更简短、更自然。
例句：
I pke eating apples because they're very sweet. (我喜欢吃苹果，因为它们很甜。)
She doesn't pke carrots because they're not sweet. (她不喜欢胡萝卜，因为它们不甜。)
He only eats candy because they're sweet. (他只吃糖果，因为它们甜。)