Although new problems ______ during the last experiment, they didn’t give up.
The computer, help we human beings have stepped into the information age, should be regarded as one of the most important inventions in the 20th century.
The little boy, out of curiosity, _______ the toy to see how it worked, but couldn’t put it together.
–Do you need any help, Lucy?--Yes. The job is I could do myself.
These flowers should not be watered too ______, once _____.
It is said that the software on learning subjects for pupils in a very practical way.