Separation of the constituents in a chromatogram can accordingly be improved in principle if: (a) either the ______ of the substances are selectively altered or, (b) the ______ is kept as low as possible.
举一反三
- Either a low injection pressure or a leakage of piston rings is able to lead （）.
- Under normal circumstances the body can ( ) these naturally occurring substances into
- To learn English well, read () after class. A: so much as possible B: as possible as you can C: as much as you can D: as many as possible
- The school headmaster played the ________ role in the faculty play. A: principle B: principal C: possible D: plentiful
- Foreign money can be convenedat this bank. A: altered B: changed C: bought D: sold