Scientists photographed for the first time ever _____ wild gorillas used a stick to test the depth of a pool before getting into it, according to a recent study.

The boy is very brave. I _______ he ________ the tall tree.

I can’t thank you too much for your kindness because without your help I        have won the first prize in the speech contest．

I will appreciate ______ if you can give me a hand.

 Her friend did everything in his ________ to help with her business.