如图所示,竖直杆OB顶端有光滑轻质滑轮,轻质杆OA自重不计,可绕O点自由转动,OA=OB.当绳缓慢放下,使∠AOB由0°逐渐增大到180°的过程中(不包括0°和180°),下列说法正确的是(A是结点)A.AB绳上的拉力先逐渐增大后逐渐减小 B.OA杆上的压力先逐渐减小后逐渐增大C.AB绳上的拉力越来越大,但不超过2GD.OA杆上的压力大小始终等于G
Why did you buy so many flowers?
________my wife.I did something wrong yesterday.She is still angry with me.( )
Please
To please
Pleasing
Be pleased
How was your vacation in America?
It couldn't be worse! I don't ________want to talk about it( )
even
hardly
ever
mainly
What worries him is that ______ little money he makes can't support _______family as large as his.( )
/; the
a; the
/;a
the; a
Some school teachers complain that many kids haven't got any hobbies﹣________we call playing computer games a hobby( )
unless
once
since
if
What did he say in his letter?Is everything OK with his father?
No idea.He didn't ________his parents in the letter.( )
admire
notice
mention
miss