单项选择题
If you have never planted anything, you won't be able to know the pleasure of watching the thing you have planted ______.
单项选择题 His name was on the ______ of my tongue, but I just couldn't remember.
单项选择题 Doctors often make higher ______ for their works than they should.
单项选择题 Though it was late in the night, ______ he continued to work vigorously.
