【单选题】关于牙周组织描述不正确的是
B.
牙龈是口腔黏膜的一部分,紧贴牙颈及临近的牙槽骨,血管丰富呈淡红色
C.
牙周膜是牙根与牙槽骨之间的致密结缔组织,有固定牙根的作用
【单选题】Why is physical exercise good for the heart and blood vessels?
A.
Because exercise makes hearts beat more strongly .
B.
Because exercise makes blood circulate more smoothl y.
C.
Because exercise may make human bodies rest .
D.
Because exercise may help heart muscle and blood work in bodies .
【简答题】如图,AD∥EG∥BC,AC∥EF,则图中与∠1相等的角(不含∠1)有________个,若∠1=60°,则∠AHG=________.
【简答题】SECTION A COMPOSITION (35 MIN) Some people say that physical exercise should be a required part of every school day. Other people believe that students should spend the whole school day on academic st...
【简答题】You are likely to get sick if you do not do physical exercise often.
【判断题】在图( a )所示锯齿波 -矩 形波发生器中,已知 A 1 、 A 2 均为理想运算放大器,其输出电压的两个极限值为 ± 12V ; 二极管的伏安特性如图( b )所示;设振荡周期为 T ,一个周期内 u O1 为高电平的时间为 T 1 ,占空比= T 1 / T 。 判断以下结论是否正确: A 2 与 R 4 、 R 5 、 VD 5 、 C 构成的电路具有积分功能;
【单选题】如图,已知AD ∥ EG ∥ BC,且AC ∥ EF,记∠EFB=α,则图中等于α的角(不包含∠EFB)的个数为( )
【单选题】Solutions to worrying such as smoking, drinking and physical exercise ______.
A.
make things worse if we are worried
B.
do nothing to overcome anxiety
C.
are often satisfactory for a short time
D.
merely produce physical strain to cover up mental stress
【简答题】如图,AD∥EG∥BC,AC∥EF,则图中与∠1相等的角(不含∠1)有( )个;若∠1=50°,则∠AHG=( )度。