除此之外, 与此同时: besides this, at the same time
【高70】【高76】固定短语 / phrases
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
除此之外 and 与此同时 open a sentence and take up the whole previous statement through 此 ("this"). They are always followed by a comma. Register: press, reports, speeches.
除此之外 ("apart from this, besides this") adds or excludes depending on what follows: addition (新馆设有阅览室，除此之外，还有一间儿童书屋) or exception (我只带了一个书包，除此之外什么都没带). 与此同时 ("at the same time") links two simultaneous facts, often to move to another subject: 太阳刚落山，几乎与此同时，天上下起了大雨.
Compare 除此之外 with 除了……以外 / 之外 (hsk3-g09): that one frames a noun or a clause (除了他之外), whereas the 此 of 除此之外 already sums up the previous sentence. For a simple "also", 此外 or 另外 are enough; keep 与此同时 for real simultaneity or parallel developments.
Examples
我只带了一个书包，除此之外什么都没带。
Wǒ zhǐ dài le yí ge shūbāo, chúcǐ zhīwài shénme dōu méi dài.I only brought one bag and nothing else.
他是我的邻居，除此之外，我对他不太了解。
Tā shì wǒ de línjū, chúcǐ zhīwài, wǒ duì tā bú tài liǎojiě.He is my neighbour; apart from that I don't know him well.
新馆设有阅览室和自习区，除此之外，还有一间儿童书屋。
Xīnguǎn shèyǒu yuèlǎnshì hé zìxíqū, chúcǐ zhīwài, háiyǒu yì jiān értóng shūwū.The new building has reading rooms and a study area; besides these, there is a children's reading room.
太阳刚落山，几乎与此同时，天上下起了大雨。
Tàiyáng gāng luòshān, jīhū yǔcǐ tóngshí, tiānshàng xiàqǐ le dàyǔ.The sun had just set when, almost at the same moment, heavy rain began to fall.
公司宣布涨价，与此同时，不少顾客开始转向其他品牌。
Gōngsī xuānbù zhǎngjià, yǔcǐ tóngshí, bùshǎo gùkè kāishǐ zhuǎnxiàng qítā pǐnpái.The company announced a price rise, and at the same time many customers began turning to other brands.
本市推出了新线路，与此同时，旧线路的班次也作了调整。
Běnshì tuīchū le xīn xiànlù, yǔcǐ tóngshí, jiù xiànlù de bāncì yě zuò le tiáozhěng.The city launched a new route and at the same time adjusted the timetables of the old ones.
Common mistakes
✗ 除此之外他，我不知道别人。 → ✓ 除了他之外，我不知道别人。 (before a noun or a pronoun, use 除了……之外: 此 already sums up the whole previous sentence).
✗ 我喜欢茶，与此同时我也喜欢咖啡。 → ✓ 我喜欢茶，另外我也喜欢咖啡。 (与此同时 expresses the simultaneity of two facts, not a simple "also": use 另外 or 此外).