It is essential that ______(你得认真阅读合同) before you sign it.

单项选择题Who once had to learn the Auto-Tune technique from T-Pain

单项选择题In 2008, scientists encountered the top of the ionosphere all______.

单项选择题The author gave it his best shot because ______.

单项选择题A．She thinks she is behind in her study.B．She only has time to study in the evenings.C．She has no time to study in the evenings.D．She thinks work is easier than study.

填空题Contrary to the prediction of some financial experts, ______(经济正在萎缩而不是在增长).

填空题subject

填空题Which word(s) in the passage can best replace the phrase natural selection

单项选择题A．ingredientB．incidentC．illusionD．impression

填空题______(尽管环保组织强烈反对), the Brazilian government has pressed on with its efforts to exploit rain forest resources.

单项选择题What has happened to T-Pain since 2005