________ these experiments were successfully completed would we think of going into humans.

A. If only  B. Only if    C. So that     D. Even if

In our life, we will have a lot of time to feel low. If there’s one thing that ruins us, which   48  us from doing what we’re   49  capable of and prevents us from achieving our dreams, it is fear of   50 .
Many of us go through our lives never knowing what we could have done and what has often been heard is that if only we hadn’t given up our   51 .
What if you had given up on   52  to talk, walk, read, ride a bike, or any other achievements before you were even five years old? How   53  would your life have turned out if you’d given up instead of    54  with them?
Now, how different has your life been because of the goals you gave up? Because you were afraid that you would fail, how many experiences and opportunities have you   55  out on because you couldn’t get past that invisible barrier of fear!?

If only he _______ quietly as the doctor instructed, he would not suffer so much now.

    A. lies                             B. lay

    C. had lain                         D. should lie

If only I had got up a little earlier this morning! I ??? the bus by only a minute and waited half an hour for another.

A.was missed???? B. have missed????????????? C. miss????????? ????????????? ????????????? D. missed

 —Did you meet with the famous space hero , Yang Liwei ?

    — ______ I had come here earlier !

         A．If only        B．If not         C．But for      D．For fear