This book is a bit difficult. ________ read something easier

the earth, Mars is too cold and Venus is fartoo hot _______ there to be any life

Planning so far ahead ________ no sense—so manythings will have changed by next year.

In a way, ________global warming is a challenge for man, so we must overcome it to build ________ fine world.

If you have any difficulties，please do not________to contact our Customer Service Department.[ ]