TheUnitedStatesisacountry_(advance)inscienceandtechnology
爱情具有双重属性，即自然和社会属性，爱情的本质是由它们共同决定的
Manyothernewtechniquesarenowavailablethatenablemoreresearch___(do)inthetesttubetoseeifchemicalsproduceharmfulbiologicaleffects.
Ifyouhadbeeninbetterhealth,we___(allow)youtojointheminthework.
Decisiononwhetherthemessageisrightorwrongshouldatleastcomeafter_____whatthemessageis.
