6.2+12.6+2.8+7.4的值为( )。A．29 B．28 C．30 D．2

A client with type 1 (insulin-dependent) diabetes mellitus who is a multigravida visits the clinic at 28 weeks’ gestation. Which of the following instruction by the nurse is appropriate for the client

A. Nonstress testing is performed weekly until 32 weeks’ gestation.
B. Weekly fetal movement counts are made by the mother.
C. Contraction stress testing is performed weekly.
D. Induction of labor is begun at 34 weeks’ gestation.

已知x，y，z∈R^＋，且x＋y＋z＝1

(1)若2x²＋3y²＋6z²＝1，求x，y，z的值．

(2)若2x²＋3y²＋tz²≥1恒成立，求正数t的取值范围．

阿根廷和智利之间的国界线是（　　）

A．设立界碑为标志

B．设立栅栏为标志

C．设立界墙为标志

D．安第斯山为界

合同评审是指，（），为了确保质量要求规定得合理、明确并形成文件，且供方能实现，由供方所进行的系统的活动。

A、合同签订前

B、检测工作开始后

C、合同执行后

D、合同执行前

证券公司公布的融资保证金比例、融券保证金比例及维持担保比例，不得超出交易所规定的标准。( )