As intriguing as these results are, much remains unclear about the impact of low doses of a low doses of alcohol ______ system.

单项选择题Many feared that the continuing insecurity would ______ the chances of elections being held successfully.

单项选择题A lateral move that hurt his pride and blocked his professional progress ______ him to abandon his relatively high profile career.

单项选择题He has impressed his employers considerably and ______ he is soon to be promoted.

单项选择题They have vowed to protect the country's territorial ______ which is one of the bases for the country to develop relationships with other countries.

单项选择题The school ______ a public debate on whether they should build a new computer laboratory or not.

单项选择题Many proverbs ______ in ancient Greece and Rome and in medieval Europe, spreading from country to country in Latin texts.

单项选择题Now that we have succeeded in isolating this drug, our next problem is to plan its in the laboratory.

单项选择题The President has again ______ with Congress over his budget plans.

单项选择题One reason for the success of Asian immigrants in the U.S. is that they have taken great ______ to educate their children.

单项选择题Key resources are technical personnel and aircraft spare parts which account for the largest share of the maintenance ______.