单选题 The environmental problems are of global importance, and only an international effort would ______ to deal with them.

单选题 Although cats cannot see in complete darkness, their eyes are much more ______ to light than human eyes.

单选题 I am sure that with your remarkable ability and rich experience, the current session you ______ over will be a success.

单选题 ______ his pioneering work in the late 1930s, Earl Hines has been called the father of modern jazz piano.

单选题 Every year schools all over the country will ______ new students the first week in September.

单选题 Some taxonomists, particularly those working in herbaria and providing an identification service, do need such ______.

单选题 In this book the writer describes in great detail how these birds ______ their young.

单选题 If you want to clarify the fact, you need two witnesses to ______ that this is your signature.