Good ideas are only useful if you can make something out of
3个回答

1. 本身无不正常语序.(下行的写法更自然.)

2. 可写成:Good ideas are useful only if you can make something out of them.

3. 是句号,不是问号.

4. 要用问号,就:

-----Are good ideas only useful if you can make something out of them? 或:

-----Are good ideas useful only if you can make something out of them? (此句更自然.)