optional的音标

We also recommend a full day optional excursion to the Upper Douro.我们还推荐去杜罗河上游的短途自选一日游。The course consists of ten core modules and five optional modules.这门课程包括十个必修单元和五个选修单元。Certain courses are compulsory, others are opti...

adj.可选择的，随意的，任意的，非强制的，选修科目...

Optional extras include cooking tuition at a top restaurant...可选的额外项目包括在顶级餐厅学习厨艺。The goods are optional, but only one.这些物品是可以任选的, 但只能选一个。Elevation view of a tapered key with optional gib head.具有可选钩头的锥形键的正视图.The third col...

optional的近义词/同义词有：voluntary, elective, voluntary, elective。adj.optional的近义词（自愿的,志愿的）：voluntary, elective。optional的近义词（其他释义）：voluntary, elective。...

optional的反义词有：compulsory, required, compulsory。adj.optional的反义词（随意的;选修的）：compulsory。optional的反义词（其他释义）：required, compulsory。...