首先，教科书也有可能有印刷错误。其次，有一些固定结构可能不需要加冠词或
定冠词或其他
限定词，当然大部分情况下应该是需要的。最后system既是可数名词又是
不可数名词。两者意思不同。
system
/ ˈsɪstəm; ˋsɪstəm/ n
[C] group of things or parts working together as a whole 系统; 组合装置: the nervous system
神经系统 * the digestive system
消化系统 * a railway system 铁路系统 * a stereo system, eg a record-deck, an amplifier, loud-speakers, etc combined
立体声音响设备 * The lifting device is a system of ropes and pulleys. 这种起重装置是由缆索和滑轮组成的.
[C] person's or animal's body as a whole, including its internal organs and processes （人或动物的）身体: The poison has passed into his system. 毒物已进入他的体内. * Alcohol is bad for your system. 喝酒对身体有害.
[C] set of ideas, theories, principles, etc according to which sth is done （思想﹑ 理论﹑ 原则等的）体系, 体制, 方法, 方式: a system of philosophy 哲学体系 * the democratic system of government 民主政体 * a good system of teaching languages 教授语言的良好方法 * a foolproof new system for winning at roulette 轮盘赌必胜新法.
[U] orderly way of doing things; tidy arrangement 制度; 步骤; 条理: You'll find little system in his method of work. 他的工作方法无甚条理. * We must introduce some system into our office routine. 我们须在我们日常公务中建立一些制度.
the system [sing] (infml 口) the traditional methods, practices and rules existing in a society, an institution, a business, etc （某社会﹑ 机构﹑ 企业等中）沿袭已久的方法﹑ 做法和规则: You can't beat the system, ie You must conform to it. 老规矩触动不得（必须照办）.
(idm 习语) get sth out of one's `system (infml 口) get rid of a strong feeling or desire by expressing it openly or trying to fulfil it 宣泄强烈的感情或满足强烈的愿望: He desperately wants to be an actor, so you'll have to give him time to get it out of his system. 他渴望当演员, 你就得容他时间让他施展自己的抱负.
> systematic / ˏsɪstəˈmætɪk; ˏsɪstəˋmætɪk/ adj
1 done or acting according to a system or plan; methodical 有系统的; 有计画的; 有条理的: the systematic arrangement of the chairs 按照顺序排列的座椅 * He's very systematic in all he does. 他做一切事情都很有条理.
2 [attrib 作定语] (derog 贬) planned in advance and done with malicious thoroughness and exactness 有预谋的; 蓄意的: a systematic attempt to ruin sb's reputation 蓄谋破坏某人的名誉. systematically / -klɪ; -klɪ/ adv.
systematize, -ise / ˈsɪstəmətaɪz; ˋsɪstəməˏtaɪz/ v [Tn] arrange (sth) according to a well-organized system 使（某事物）系统化或有条理; 使（某事物）成制度或成体系: We must try to systematize the way we do the accounts. 我们必须力求把记帐方法制度化. systematization, -isation / ˏsɪstəmətaɪˈzeɪʃn; US -tɪˈz-; ˏsɪstəmətɪˋzeʃən/ n.
systemic / sɪˈstemɪk, also sɪˈstiːmɪk; sɪsˋtɛmɪk/ adj 1 of or affecting the whole of the body 全身的; 影响全身的. 2 acting by entering the tissues of a plant and killing insects and other pests which try to feed on it 内吸收的, 内吸性的（通过渗入植物组织内以消灭以之为食的昆虫及其他有害生物的）: systemic fungicides 内吸性杀真菌剂. systemically / -klɪ; -klɪ/ adv.
# `systems analysis analysis of all the steps in an operation in order to decide how to perform it most efficiently, esp using a computer 系统分析（尤指用计算机）. `systems analyst expert in systems analysis 系统分析专家.
【C】指可数名词，【U】指不可数名词。
最后……我想问一下，in system您确定有这种说法吗，如果不是提问令师的结果最好还是用study systematically比较好……