____ difficult the task may be, we will try ourbest to complete it in time.

Think it over， ______ you’ll work out the math problem.

you are familiar with the author’sideas, try reading all the sections as quickly as possible

So far we have done a lot to build a low-carbon economy, but it is________ idealWe have to work still harder

He bought whatever caught his eye in the store _______ he often went .