這一句算是完整的一句英文句嗎?

Question

I saw this sentence from an English-English dictionary. Man, it does not
look like a complete sentence according to the grammatical rule. What you guys think about it?

If she could only channel all that nervous energy into something useful.

Answer 1

if only 是用於陳述不可能成真的強烈空想，因為都是不可能成真的願望或對過去事實不可能改變的那種"早知如此 何必當初"的感受，所以時態上就是與現在事實或過去事實相反的假設語氣，這也正是Longman字典所解釋的：
a) used to express a strong wish, especially when you know that what you want cannot happen:
If only he had talked to her sooner!
If only I weren't so tired!
其實這是省略半段句子的簡略表達方式，但是因為表達空望的意思很清楚明顯，所以也就簡略的半句來說，語氣上更能襯托那種空望的渴切，原先完整的句子應該是這樣的：
It would have been great if only he had talked to her sooner. 當時要是他能早一點跟她談談該有多好
It would be great if only I weren't so tired. 要是我不這麼累該有多好　
這種簡略句當完整句用的，是有一些，像是也很常聽到的 ：
So far so good. (It's been so good so far.)
而版主提出的句子：
If she could only channel all that nervous energy into something useful.
有把"only"一字後移，原先應該是：
If only she could channel all the nervous energy into something useful.
要是她能把精力放在有意義的事情上多好
這簡略句就很清楚了 ．

Answer 2

是的,這是一個完整的句子哦!!!!!

那翻起來就是:

如果 她能夠把所有緊張的能力(情緒)都傳移到有用的事情上。

channel在這裡當做 動詞 意思即為 ：傳移 或 導向.......

有種分散注意力的那種意思 。

希望可以幫到你..........