Many animals ____in the trees. A: A.to live B: B.are lived C: C.living D: D.live

The boy ______ the window now. A: A.is cleaning B: B.are cleaning C: C.clean D: D.cleaned

Jim, here _________ some letters for you. A: A.is B: B.are C: C.have D: D.Has

表达式Left("how are you",3)的值是 A．how B．are C．you D．how are you

The old over 90 _______ not only by their family but also by the government in many places． A: A．is looked at B: B．are taken good care of C: C．are taken good care D: D．is looking after

Whichtwowordsareclosestinmeaning?<br/><b>cycle</b><b>，</b><b>hawk</b><b>，</b><b>convey</b><b>，</b><b>extort</b><b>，</b><b>peddle</b><b>，</b><b>summon</b>

设A{a,b}，则P(A)×A = (   )。 A: A B: P（A） C: {<Φ,a>,<Φ,b>,<{a},a>,<{a},b>,<{b},a>,<{b},b>,<A,a>,<A,b>} D: {<a,,Φ,>,<b,,Φ,>,<a,{a}>,<b,{a}>,<a,{b}>,<b,{b}>,<a,A>,<b,A>}

以下哪段代码可以将A,B的值互换（） A: A=A^B; B=A^B;A=A^B B: A= A^B;A=A^B;B=A^B C: B= A^B; B=A^B; A=A^B D: B=A^B; A= A^B; A= A^B

若集合A={a，b}，B={ a，b，{ a，b }}，则（）。 A: A⊆B，且A∈B B: A∈B，且B⊆A C: A⊈B，且A∉B D: A∉B，且A⊈B

设论域D={a,b}，与公式[img=504x85]17d6234b6469e12.png[/img]等价的命题公式是（ ） A: (A（a）∧A（b）) → (B（a）∧B（b）) B: (A（a）→B（a）)∨(A（b）→B（b）) C: (A（a）∨A（b）) → (B（a）∨B（b）) D: (A（a）→B（a）)∧(A（b）→B（b）)