EM是

A:化学文摘 B:医学文摘 C:医学索引 D:国际药学文摘 E:中国药学文摘

Ep＝（）Em

A:2 B:1/π C:2/π D:3/π

212，214，217，222，230，（）

A:232 B:238 C:242 D:258

Do the suffixes -able in workable, -ness in workableness change the word class of the words to which they are attached Are they bound morphemes or free morphemes Inflections or derivations

The suffixes -able in workable and -ness in workableness have changed the word class of the words to which they are attached．They are bound morphemes，though -able is both a free and bound morpheme．They are derivational morphemes．

已知测站点高程为H_A时，则立尺点的高程
H_B=H_A+h=H_A+i-l式中h为两点高差、i为仪器高、l为目标高上式称视准轴水平时的视距测量计算式。( )

251，222，193，( )。

A:65 B:205 C:164 D:134

设变量$x,y$满足约束条件$\left\{\begin{array}{l}x+y-2⩾0\\ x-y-2⩽0\\ y⩾1\end{array}\right.$,则目标函数$z=x+2y$的最小值为$($$$$)$

A: $2$$$ B: $3$$$ C: $4$$$ D: $5$

在平行六面体$ABCD$-$A_1{B}_1{C}_1{D}_1$中，设$\overrightarrow{A{C}_1}$=$x\overrightarrow{AB}$+$2y\overrightarrow{BC}$+$3z\overrightarrow{C{C}_1}$，则$x+y+z$等于$($$$$)$

A: 1 B: $\frac{2}{3}$$$ C: $\frac{5}{6}$$$ D: $\frac{11}{6}$