So it's OK to not specify. I want to point out, pz whether you're in the p x, the p y, or the p z, unless a question specifically m asks you to specify the m sub l, which occasionally will happen, but if it doesn't happen you just write it like this.

我想指出的是，无论你在px，py或，除非一个问题特别地,让你指出l下面的，这种情况有时会发生，这样就可以了,但是如果它不做要求你们写成。

麻省理工公开课 - 化学原理课程节选

The EOS 6D will even allow photographers to specify a previously captured RAW image as the starting point for a new Multiple Exposure composite image.

ENGADGET: Canon unveils EOS 6D DSLR: full frame sensor and WiFi for $2,099 in December

Point out that the U.S. Constitution does specify a system for the election of the president, known as the Electoral College.

CNN: Lesson plan: The electoral process

As for availability, we heard that this S2109 will launch at some point this month, though our shy friend didn't specify which market it'll debut in -- the FCC document lists Germany, Canada, US, India, Russia, Turkmenistan, Mexico, Chile, Japan and China.

ENGADGET: Lenovo IdeaTab S2109 teased by FCC, launching with 9.7-inch display this month?